Functional visual head pulse testing

Abstract

A functional visual head pulse test is disclosed in which a system for evaluating vestibular system function of a subject includes: an eye measurement device configured to record a pupil position, a velocity value, and / or an acceleration value of at least one eye; the motion sensing device is configured to provide at least one motion signal representing an acceleration value and / or a speed value of rotation of the head of the tested object in at least one plane; a display device; a user input device; a processing device; the processing device is configured to execute at least one of a plurality of test protocols, wherein one test protocol includes: continuously analyzing at least one motion signal from the motion sensing device and determining a point in time having a maximum acceleration value; presenting an image characterized by a characteristic for a predetermined time interval starting from the determined point in time having the maximum acceleration value; receiving a user input comprising an estimate of a characteristic of the image; the processing device is configured to determine a correspondence between the characteristic and the estimate.

Description

Technical Field

[0001] The present application relates to a system for evaluating the function of the vestibular system of a subject.

[0002] The present application also relates to a method for evaluating the function of the vestibular system of a subject.

[0003] The present application also relates to a data processing system including a processing device and program code, the program code causing the processing device to execute at least part of the steps of the above method.

[0004] The present application also relates to a computer program including instructions that, when run by a system, cause the system to execute the steps of the above method. Background Art

[0005] The vestibular ocular reflex (VOR) is an eye movement that enables the gaze / line of sight of a subject (i.e., a patient) to remain focused on a target during head movement.

[0006] The VOR can be evaluated using different techniques. These techniques include video goggles connected to cameras and accelerometers that measure eye velocity and head velocity. From the measurement results, the gain can be determined, which is the eye velocity divided by the head velocity. Other techniques use only a head-mounted accelerometer to measure head velocity and rely on the subject's response to a visual target presented on a screen in front of the subject to measure visual acuity. Visual acuity is a functional measurement, while gain is an objective mathematical measurement.

[0007] In other words, the purpose of VOR testing / techniques is to evaluate the function of the vestibular system (i.e., including the vestibular semicircular canals and the associated vestibular ocular reflex (VOR)). The function of the peripheral vestibular apparatus can be tested using two types of measurements: (1) the "traditional" video head impulse test (vHIT) measures the angular VOR (aVOR) gain - estimating reduced gain and corrected eye movements; and (2) evaluating the more recent functional gain using visual acuity as a measure of how well the aVOR performs in stabilizing the line of sight during head movement. The vHIT is performed passively as the clinician (i.e., the user operating the system) moves the head. Functional testing has traditionally been a passive test where the clinician moves the subject's head. However, for example, active tests are also known where the subject can move their own head in response to the sound of a metronome (or in response to clinician instructions) to produce the VOR gain. This may be a better measure of vestibular system function because daily life situations involve the subject actively moving their own head. However, none of these tests provide a determination of VOR function at maximum head acceleration because, briefly, existing systems cannot display a visual target at maximum head acceleration.

[0008] Therefore, there is a need to provide a system suitable for determining the VOR function at maximum acceleration. Summary of the Invention

[0009] System

[0010] In one aspect of the present application, there is provided a system for evaluating the vestibular system function of a subject.

[0011] There is also provided a device or instrument including all units of the above system.

[0012] The system may include an eye measurement device.

[0013] The eye measurement device may be configured to record (e.g., measure and store) the pupil position of at least one eye of the subject.

[0014] The eye measurement device may be configured to generate a pupil position signal. The pupil position signal may include information about the velocity value and / or acceleration value of at least one eye of the subject.

[0015] The eye measurement device may be configured to record the velocity value of at least one eye of the subject.

[0016] The eye measurement device may be configured to record the acceleration value of at least one eye of the subject.

[0017] The pupil position may refer to the position or direction of the subject's eye.

[0018] At least one eye may refer to one or both eyes of the subject.

[0019] For example, from the pupil position of at least one eye of the subject, the system (or the eye measurement device) may be configured to determine the direction of the line of sight (or the focal point of the eye) relative to the display.

[0020] For example, the eye measurement device may be a binocular camera system.

[0021] For example, the eye measurement device may be a (video) goggle including a recording device such as a camera.

[0022] The system may include a motion sensing device.

[0023] The motion sensing device may be configured to sense at least the movement of the subject's head.

[0024] The motion sensing device may be configured to sense at least the position of the subject's head.

[0025] The motion sensing device may be configured to provide at least one motion signal representing the acceleration value of the rotation of the subject's head in at least one plane.

[0026] Alternatively or in addition, at least one motion signal may represent a speed value of the rotation of the subject's head in at least one plane.

[0027] The acceleration value may refer to the magnitude of the acceleration expressed in degrees per square second (° / s 2 ), and the speed value may refer to the magnitude of the speed expressed in degrees per second (° / s).

[0028] For example, the motion sensing device may be a 9-degree-of-freedom (DOF) inertial measurement unit (IMU) sensor.

[0029] The system may include a display device.

[0030] The display device may be configured to display at least one image.

[0031] For example, the display device may be a PC monitor or screen.

[0032] The system may include a user input device.

[0033] The user input device may be adapted (configured) to receive user input.

[0034] For example, the user input may be provided by a user of the system (such as a medical examiner and / or a clinician) or may be provided by the subject. For example, the user input may be a user or subject pressing a button or switch on the user input device.

[0035] The system may include a processing device.

[0036] The processing device may be connected to the eye measurement device, the motion sensing device, and the display device. The processing device may also be connected to the user input device.

[0037] The term "connected to" may mean that the processing device is "connected" or "coupled" to other elements during operation. In other words, the processing device may be directly connected or coupled to other elements, but there may also be additional intermediate elements (such as a transmission / receiving unit) unless otherwise expressly stated. In addition, "connected" or "coupled" as used in this application may include a wireless connection or coupling. For example, the processing device may be configured to send and / or receive control signals / information / data via the connection.

[0038] The processing device may be configured to execute at least one of a plurality of test protocols.

[0039] The processing device may be configured to execute and / or start at least one of a plurality of test protocols in response to receiving a start / initiation signal (such as a user input via the user input device).

[0040] Multiple test protocols include, for example, a Video Head Impulse Test (vHIT) protocol, a Functional Vision Head Impulse Test (fvHIT) protocol, an Active Head Rotation (AHR) protocol, a Dynamic Visual Acuity (DVA) protocol, a Gaze Stabilization Test (GST) protocol, and / or a Visual Process Time (VPT) protocol. One of the (multiple) test protocols may include the steps of continuously analyzing at least one motion signal from a motion sensing device and determining a time point with a maximum acceleration value.

[0041] One test protocol may further include presenting, via a display device, the image characterized by a characteristic for a preset time interval starting from the determined time point with the maximum acceleration value.

[0042] For example, the preset time interval may be at least 30 ms.

[0043] For example, the preset time interval may be less than 100 ms.

[0044] For example, the preset time interval (or the minimum time required to present the image) may be determined by a VPT test before executing the test protocol.

[0045] One test protocol may further include receiving, via a user input device, a user input including an estimate of the characteristic of the image.

[0046] Thus, multiple test protocols may include an fvHIT protocol, which at least includes:

[0047] - Continuously analyzing at least one motion signal from a motion sensing device and determining a time point with a maximum acceleration value;

[0048] - Presenting, via a display device, the image characterized by a characteristic for a preset time interval starting from the determined time point with the maximum acceleration value;

[0049] - Receiving, via a user input device, a user input including an estimate of the characteristic of the image.

[0050] The processing device may be configured to determine the correspondence between the characteristic and the estimate of the characteristic.

[0051] Thus, a system suitable for determining the VOR function at maximum acceleration is provided.

[0052] The display device may be configured to display at least one image.

[0053] Thus, the image may be visible to a subject.

[0054] At least one image may include a visual target.

[0055] At least one image may include one of a plurality of visual targets.

[0056] The display device may be configured to display one of a plurality of visual targets in response to receiving user input via a user input device.

[0057] Thus, the user may select the image (e.g., visual target) that is most suitable for the test protocol to be performed.

[0058] The characteristics of at least one image may be related to the orientation of the image.

[0059] For example, the image may be a Landolt C visual target.

[0060] For example, the image may be a Tumbling E visual target.

[0061] For example, the image may be a VisualEyes C visual target.

[0062] The visual target may be oriented to the left, right, top, or bottom of the display device.

[0063] The characteristics of at least one image may be related to the size of the image.

[0064] The characteristics of at least one image may be related to the position of the image.

[0065] For example, the image may be displayed at different positions on the display device, such as the center of the display device or one of the edges of the display device.

[0066] The characteristics of at least one image may be related to the contrast of the image.

[0067] The step of continuously analyzing at least one motion signal from a motion sensing device and determining the time point with the maximum acceleration value may include: the processing unit comparing the acceleration value of each of the at least one motion signals with a pre-determined acceleration threshold.

[0068] For example, the pre-determined acceleration threshold may be at least 750° / s 2 . Thus, the pre-determined acceleration threshold may be, for example, 750° / s 2 , 800° / s 2 , 850° / s 2 , 900° / s 2 , etc. or any value therebetween.

[0069] The step of continuously analyzing at least one motion signal from a motion sensing device and determining a time point with a maximum acceleration value may include: the processing unit comparing the velocity value of each of the at least one motion signal with a pre-determined velocity threshold.

[0070] For example, the pre-determined velocity threshold may be at least 40° / s. Thus, the pre-determined velocity threshold may be, for example, 40° / s, 45° / s, 50° / s, 55° / s, etc. or any value therebetween.

[0071] The step of continuously analyzing at least one motion signal from a motion sensing device and determining a time point with a maximum acceleration value may include: the processing unit presenting a start signal in response to both the acceleration value and the velocity value exceeding respective thresholds.

[0072] The start signal may be presented at a time point earlier than the time point with the maximum acceleration value. In other words, there is a time delay between this earlier time point and the time point with the maximum acceleration value. This time delay may be, for example, at least 20 ms such as 30 ms.

[0073] For example, the start signal may represent a time point estimated before the acceleration value reaches its actual maximum. In other words, the start signal may be presented with a time delay before the maximum acceleration value (estimated time).

[0074] The time delay may represent the latency of the system, for example, the graphics part of the system, such as the latency in software for processing image display and in the display device.

[0075] The step of presenting, by a display device, the image characterized by a characteristic for a preset time interval starting from the determined time point with the maximum acceleration value may include: presenting the image by the display device in response to the presentation of the start signal by the processing unit.

[0076] The characteristic of the image may be determined by an executed test protocol.

[0077] The step of receiving, via a user input device, a user input including an estimate of the characteristic of the image may include receiving a response from a subject under test or from a user of the system.

[0078] In other words, when the subject's head rotates with maximum acceleration, an image (such as a visual target) may be displayed on the display device for the subject to view. Thereafter, the subject or a user of the system may (via the user input device) provide to the system a user input including an estimate of the characteristic of the image, which may, for example, include an indication of the orientation of the image.

[0079] The processing device can be configured to score the percentage of correct estimation (i.e., from the subject) of the characteristic at different rotational accelerations of the subject's head in each corresponding plane.

[0080] The processing device can be configured to re - execute a specific test protocol in response to receiving an instruction in the form of a user input via the user input device.

[0081] For example, when a specific test protocol has been executed, such as where the subject's head has rotated and a visual target has been displayed at maximum head acceleration, a clinician may want to repeat the test protocol. This can be initiated in response to the clinician providing a user input, such as an instruction / control signal, to repeat the test protocol.

[0082] The processing device can be configured to execute a specific test protocol among a plurality of test protocols in response to receiving an instruction to execute the specific test protocol among the plurality of test protocols via the user input device.

[0083] Thus, when one or more test protocols are to be repeated, the user can design which test protocol will be executed.

[0084] At least one plane can include the transverse plane.

[0085] At least one plane can include the right - anterior, left - posterior (RALP) plane.

[0086] At least one plane can include the left - anterior, right - posterior (LARP) plane.

[0087] At least one plane can include the sagittal plane.

[0088] The transverse plane can refer to head rotation in the horizontal plane. For example, the subject's head can be bowed forward by about 30 degrees. Thus, the horizontal canals of each ear (which are in a coplanar pair) are optimally simulated.

[0089] The RALP plane can refer to head rotation in a direction that optimally simulates the right - anterior, left - posterior coplanar pair.

[0090] The LARP plane can refer to head rotation in a direction that optimally simulates the left - anterior, right - posterior coplanar pair.

[0091] The motion - sensing device can be configured to connect to the eye - measuring device.

[0092] The motion - sensing device can be releasably connected to the eye - measuring device.

[0093] Thus, the motion - sensing device can be connected before executing a specific test protocol and then disassembled again after that when it is not relevant to the next test protocol.

[0094] Alternatively, the motion - sensing device can be positioned on the subject's head using a headband, thus not being directly connected to the eye - measuring device.

[0095] For example, the motion sensing device may include a single motion sensor such as an accelerometer, which may be located at the central position of the eye measuring device, such as the forehead of the subject. Alternatively, the motion sensing device may include more than two motion sensors, such as two accelerometers, which may be located near each eye of the subject, for example.

[0096] The display device may include a refresh rate of at least 240 Hz.

[0097] The refresh rate may refer to the scanning rate of the display device, such as the scanning rate of a monitor.

[0098] For example, the refresh rate may even be higher, as this will only increase the reliability of displaying the image at the correct moment.

[0099] The user input device may include a remote control.

[0100] The remote control may enable the subject to easily provide his / her estimate of the image characteristics.

[0101] The user input device may include a keyboard.

[0102] The user input device may include a touch screen.

[0103] The processing device may be configured to execute at least one of a plurality of test protocols.

[0104] The plurality of test protocols may include an AHR test protocol.

[0105] For example, the system may include an eye measuring device such as goggles having a camera configured to record at least one eye of the subject. The system may also include a motion sensing device such as an accelerometer worn on the subject's head. The motion sensing device may be connected to the eye measuring device. The system may also include a processing device configured to execute the AHR test protocol.

[0106] The AHR test protocol may include (at a plurality of head rotation speed values):

[0107] - presenting the image characterized by a characteristic through the display device;

[0108] - continuously analyzing at least one motion signal from the motion sensing device and determining the speed value of the subject's head rotation;

[0109] - continuously determining the speed value of at least one eye of the subject through the eye measuring device;

[0110] - determining a gain value by dividing the eye speed by the head speed.

[0111] For example, the head can rotate at multiple different frequencies. These frequencies can be, for example, 1 - 3 Hz or higher. In other words, the AHR test protocol can include the user / clinician moving the subject's head left or right in a controlled sinusoidal motion timed with a metronome. Meanwhile, the display device can display a stationary image. The processing device can measure the gain, which is the eye velocity divided by the head velocity (as well as phase and asymmetry) at different head rotation frequencies.

[0112] Multiple test protocols can include the vHIT test protocol.

[0113] For example, the system can include an eye measurement device such as goggles with a camera that records at least one eye of the subject. The system can also include a motion sensing device such as an accelerometer worn on the subject's head. The motion sensing device can be connected to the eye measurement device. The system can also include a processing device configured to execute the vHIT test protocol.

[0114] The vHIT test protocol can include:

[0115] - presenting the image characterized by a characteristic through the display device;

[0116] - continuously analyzing at least one motion signal from the motion sensing device and determining the velocity value of the subject's head movement;

[0117] - continuously determining the velocity value of at least one eye of the subject through the eye measurement device;

[0118] - determining the gain value by dividing the eye velocity value by the head velocity value.

[0119] For example, the head can be moved in a rapid pulse motion. For example, the rapid pulse motion can be + / - 15 degrees relative to the head's stationary position.

[0120] In other words, the vHIT test protocol can include the user / clinician rapidly moving the subject's head left or right in the transverse plane in a high - speed pulse motion, or in the RALP plane or LARP plane. Meanwhile, the display device can display a stationary image. The processing device can measure the gain, which is the eye velocity value divided by the head velocity value.

[0121] Multiple test protocols can include the DVA (or DVAT) test protocol.

[0122] For example, the system can include a motion sensing device such as an accelerometer worn on the subject's head. The system can also include a processing device configured to execute the DVA test protocol.

[0123] The DVA test protocol can include:

[0124] - Continuously analyze at least one motion signal from a motion sensing device and determine a speed value of the rotation of the subject's head;

[0125] - In response to the speed value reaching and / or exceeding a speed threshold, present, via a display device, an image characterized by a characteristic;

[0126] - Receive, via a user input device, a user input including an estimate of the image characteristic;

[0127] - Determine a correspondence between the characteristic and the estimate of the characteristic.

[0128] The DVA test protocol may further include:

[0129] - In response to the correspondence between the characteristic and the estimate of the characteristic exceeding a correspondence threshold, compare the size of the image with the size determined at a 0° / s speed value (i.e., determined by a static DVA test protocol) of the image.

[0130] For example, the speed threshold may be at least 50° / s and / or less than 300° / s. For example, the speed threshold may be 100° / s.

[0131] In other words, the DVA test protocol may include the user / clinician moving the subject's head left and right (in the horizontal plane) or up and down (in the vertical plane) in a controlled sinusoidal motion timed with a metronome. The subject may view an image such as a visual target that appears on a display device when a certain head speed is reached. In response, the subject may indicate the direction in which the visual target is pointing. In response, the processing device may determine (e.g., score) the change in the size of the visual target required for the subject to clearly see the visual target when the head is at maximum speed and compare the determined size of the visual target with the size of the visual target required to be clearly seen when the head is not moving. The size of the visual target required when the head is not moving may be determined by reducing the size of the visual target until a threshold is found.

[0132] The plurality of test protocols may include a GST test protocol.

[0133] For example, the system may include a motion sensing device such as an accelerometer worn on the subject's head and a display device configured to display at least one image. The system may further include a processing device configured to execute the GST test protocol.

[0134] The GST test protocol may include:

[0135] - Continuously analyze at least one motion signal from a motion sensing device and determine a speed value of the rotation of the subject's head;

[0136] - In response to the speed value reaching and / or exceeding a speed threshold, present, via a display device, an image characterized by a characteristic;

[0137] - Receiving user input including an estimate of an image characteristic via a user input device;

[0138] - Determining a correspondence between the characteristic and the estimate of the characteristic.

[0139] The GST test protocol may further include:

[0140] - Scoring a speed value;

[0141] - Determining a maximum speed value when there is a correspondence between the characteristic and the estimate of the characteristic.

[0142] For example, the characteristic of at least one image may be related to the orientation of the image.

[0143] For example, the speed value may be at least 50° / s and / or less than 300° / s.

[0144] In other words, the GST test protocol may include the user / clinician / physician moving the subject's head left and right (in the horizontal plane) or up and down (in the vertical plane) in a controlled sinusoidal motion timed by a metronome at 50 - 300° / s. The subject may view an image such as a visual target on a display device when reaching a certain speed value (head speed), and in response, the subject may indicate the direction in which the image is pointing. In response, a processing device (such as software) may determine (e.g., score) the speed value and determine the maximum speed value at which the image remains clear to the subject. For example, the size of the image may be the same, but the speed value may vary.

[0145] A plurality of test protocols may include a VPT test protocol.

[0146] The VPT test protocol may include:

[0147] - Presenting an image characterized by a characteristic on a display device for a preset time interval;

[0148] - Receiving user input including an estimate of an image characteristic via a user input device;

[0149] - Determining a correspondence between the characteristic and the estimate of the characteristic;

[0150] - In response to the correspondence between the characteristic and the estimate, reducing the time interval for presenting the image;

[0151] - Determining a minimum time interval when there is a correspondence between the characteristic and the estimate.

[0152] In other words, the VPT test protocol may include presenting visual targets on the screen at different time intervals (between 30 ms and 100 ms). The test (preset time interval) starts at about 70 - 80 ms. If the subject correctly identifies the visual target, the detection threshold process starts to determine the fastest visual target that the subject can correctly identify.

[0153] The processing device may be configured to determine the visual focus of the subject on the display device.

[0154] The visual focus may be determined based on the recorded direction of at least one eye of the subject.

[0155] The recorded direction may refer to the direction of the subject's eyes relative to the display device.

[0156] The processing device may be configured to determine the average response rate calculation.

[0157] For example, the average response rate calculation may include the processing device being configured to calculate the correct response rate for each acceleration window, i.e., the proportion of correct responses for each acceleration window. The acceleration windows may be within 2000 - 7000 ° / s. For example, these windows may be divided into 1000 - 2000 ° / s, 2000 - 3000 ° / s, 3000 - 4000 ° / s, 4000 - 5000 ° / s, 5000 - 6000 ° / s, and 6000 - 7000 ° / s. The correct response rate for each acceleration window may be calculated for one or more rotation / movement planes of the subject's head.

[0158] For example, the processing device may be configured to provide the average response rate across all acceleration windows (for each rotation / movement plane).

[0159] The system may further include a timer.

[0160] The system may be configured to time the duration from presenting the image until receiving the user input.

[0161] The system may be configured to implement a (predetermined) time interval from presenting the image until the processing device presents a predetermined response. For example, the predetermined response may indicate that no response will be provided, such as "I don't know", so that the user does not have to select an answer on the computer or via a remote control. In other words, the system may be configured to record a "no response" user input in the case where the user does not provide user input within the (predetermined) time interval.

[0162] For example, the (predetermined) time interval may be 5 seconds or more.

[0163] The system may be configured to provide (real - time) feedback to the user during at least one of the execution of multiple test protocols.

[0164] For example, the feedback may be provided on a test screen, e.g., visible to the user / operator of the system (such as a medical examiner and / or clinician).

[0165] For example, the feedback may be represented as an acceleration window at the upper part of the test screen (such as an additional display device).

[0166] The system may include a room recording camera (such as an external camera (or built-in computer camera) connected to the system's computer).

[0167] The system may be configured to record a patient via the room recording camera during a test protocol. This may be beneficial for seeing head movements via video recording and matching them with test findings / evaluations.

[0168] The system may be configured to record audio via the room recording camera during a test protocol. Thus, the audio of the patient's responses / symptoms noted during the test can be recorded.

[0169] The eye measurement device may include a camera for recording at least one eye of a subject.

[0170] In another aspect, a system further including an auxiliary device is provided.

[0171] The system may be adapted to establish communication links between units of the system (such as an eye measurement device, a motion sensing device, a display device, a user input device, a processing device, an auxiliary device, etc.) so that information (such as control and / or status signals, motion signals, start signals, etc.) can be exchanged or forwarded from one unit to another.

[0172] The auxiliary device may include a remote control, a mobile device, a smart phone, or other portable electronic devices such as a tablet computer, etc., or may include a server device, etc.

[0173] The communication link may be a wired or wireless link, e.g., based on Bluetooth or some other standardized scheme.

[0174] Application

[0175] In one aspect, an application of the system as described above and defined in the claims is provided.

[0176] Method

[0177] In one aspect, the present application further provides a method for evaluating the vestibular system function of a subject.

[0178] The method may include executing at least one of a plurality of test protocols by a processing device.

[0179] One test protocol (among multiple test protocols) may include: continuously analyzing at least one motion signal from a motion sensing device that represents the rotational acceleration of the subject's head in at least one plane.

[0180] One test protocol may include: determining the time point with the maximum acceleration value.

[0181] One test protocol may include presenting, via a display device, an image characterized by a characteristic for a preset time interval starting from the determined time point with the maximum acceleration value.

[0182] One test protocol may include: receiving, via a user input device, a user input including an estimate of the characteristic of the image.

[0183] The method may further include determining the correspondence between the characteristic and the estimate of the characteristic.

[0184] A method for evaluating the vestibular system function of a subject may include executing at least one of multiple test protocols by a processing device, where one test protocol includes an AHR test protocol (at multiple head rotation speed values):

[0185] - Presenting, via the display device, the image characterized by a characteristic;

[0186] - Continuously analyzing at least one motion signal from a motion sensing device and determining the speed value of the subject's head rotation;

[0187] - Continuously determining, via an eye measurement device, the speed value of at least one eye of the subject;

[0188] - Determining a gain value by dividing the eye speed by the head speed.

[0189] The method may further include:

[0190] - Rotating the subject's head in a sinusoidal motion at a constant head speed value in at least one plane.

[0191] For example, the head can be rotated at multiple different frequencies. These frequencies can be, for example, 1 - 3 Hz or higher. In other words, the AHR test protocol may include the user / clinician moving the subject's head left or right in a controlled sinusoidal motion timed with a metronome. At the same time, the display device may display a fixed image. The processing device may measure the gain, which is the eye speed divided by the head speed (as well as phase and asymmetry) at different head rotation frequencies.

[0192] A method for evaluating the vestibular system function of a subject may include executing at least one of multiple test protocols by a processing device, where one test protocol includes a vHIT test protocol:

[0193] - Presenting the image characterized by a characteristic via the display device;

[0194] - Continuously analyzing at least one motion signal from a motion sensing device and determining a speed value of the head movement of the subject;

[0195] - Continuously determining a speed value of at least one eye of the subject via an eye measurement device;

[0196] - Determining a gain value by dividing the eye speed value by the head speed value.

[0197] The method may also be characterized by high speed, low amplitude and unexpected head movements.

[0198] For example, the head may be moved in a rapid pulse motion. For example, the rapid pulse motion may be + / - 15 degrees relative to the rest position of the head.

[0199] In other words, the vHIT test protocol may include the user / clinician rapidly moving the head of the subject left or right in the transverse plane, or in the RALP plane or LARP plane, in a rapid pulse motion. Meanwhile, the display device may display a fixed image. The processing device may measure the gain, which is the eye speed value divided by the head speed value.

[0200] A method for evaluating the vestibular system function of a subject may include executing at least one of a plurality of test protocols via a processing device, wherein one test protocol includes a DVA test protocol:

[0201] - Continuously analyzing at least one motion signal from a motion sensing device and determining a speed value of the head rotation of the subject;

[0202] - In response to the speed value reaching and / or exceeding a speed threshold, presenting an image characterized by a characteristic via the display device;

[0203] - Receiving a user input including an estimate of the image characteristic via a user input device;

[0204] - Determining the correspondence between the characteristic and the estimate of the characteristic.

[0205] The DVA test protocol may also include:

[0206] - In response to the correspondence between the characteristic and the estimate of the characteristic exceeding a correspondence threshold, comparing the size of the image with the size of the image at a speed value of 0° / s.

[0207] The method may also include:

[0208] - Rotating the head of the subject in a sinusoidal motion at a constant (head) speed value in at least one plane.

[0209] For example, the speed threshold can be at least 50° / s and / or less than 300° / s. For example, the speed threshold can be 100° / s.

[0210] In other words, the DVA test protocol can include the user / clinician moving the subject's head left and right (in the horizontal plane) or up and down (in the vertical plane) in a controlled sinusoidal motion timed by a metronome. The subject can view an image such as a visual target that appears on a display device when a certain head speed is reached. In response, the subject can indicate the direction in which the visual target is pointing. In response, the processing device can determine (e.g., score) the change in the size of the visual target required for the subject to clearly see the visual target when the head is at maximum speed and compare the determined size of the visual target with the size of the visual target required to be clearly seen when the head is not moving. The size of the visual target required when the head is not moving can be determined by reducing the size of the visual target until a threshold is found.

[0211] A method for evaluating the vestibular system function of a subject can include performing at least one of a plurality of test protocols by a processing device, wherein one test protocol includes a GST test protocol:

[0212] - Continuously analyze at least one motion signal from a motion sensing device and determine the speed value of the subject's head rotation;

[0213] - In response to the speed value reaching and / or exceeding the speed threshold, present an image characterized by a characteristic through a display device;

[0214] - Receive user input including an estimate of the image characteristic via a user input device;

[0215] - Determine the correspondence between the characteristic and the estimate of the characteristic.

[0216] The GST test protocol can further include:

[0217] - Score the speed value;

[0218] - Determine the highest speed value when there is a correspondence between the characteristic and the estimate of the characteristic.

[0219] For example, the characteristic of at least one image can be related to the orientation of the image.

[0220] The method can further include:

[0221] - Rotate the subject's head at a speed value in a sinusoidal motion in at least one plane.

[0222] For example, the speed value can be at least 50° / s and / or less than 300° / s.

[0223] In other words, the GST test protocol may include the user / clinician / physician moving the subject's head left and right (in the horizontal plane) or up and down (in the vertical plane) in a controlled sinusoidal motion timed to a metronome at 50 - 300° / s. The subject may view an image such as a visual target that appears on a display device when a certain speed value (head speed) is reached, and in response, the subject may state the direction in which he / she believes the image is pointing. In response, a processing device (e.g., software) may determine (e.g., score) the speed value and determine the highest speed value at which the image remains clear to the subject. For example, the size of the image may be the same, but the speed value may vary.

[0224] When appropriately replaced by corresponding processes, some or all of the structural features of the system described above or defined in the claims may be combined with the implementation of the method, and vice versa. The implementation of the method has the same advantages as the corresponding system.

[0225] Computer-readable medium or data carrier

[0226] The present invention further provides a tangible computer-readable medium (data carrier) storing a computer program including program code (instructions) that, when the computer program runs on a data processing system (computer), causes the data processing system to execute (implement) at least some (e.g., most or all) of the steps of the method described above and defined in the claims.

[0227] Computer program

[0228] In addition, the present application provides a computer program (product) including instructions that, when the computer program runs on a device (e.g., a system, or a unit of a system), causes the device to execute the steps of the method described above and defined in the claims.

[0229] Data processing system

[0230] On the one hand, the present invention further provides a data processing system including a processing device and program code that causes the processing device to execute at least some (e.g., most or all) of the steps of the method described above and defined in the claims.

[0231] APP

[0232] On the other hand, the present invention also provides a non-transitory application called APP. The APP may include executable instructions configured to run, for example, by a system or on a unit of the system or on an auxiliary device such as a display device or a user input device to, for example, implement a control interface (user interface). BRIEF DESCRIPTION OF THE DRAWINGS

[0233] Aspects of the present invention will be best understood from the following detailed description taken in conjunction with the accompanying drawings. For clarity, the drawings are schematic and simplified, showing only the details necessary for understanding the present invention and omitting other details. Throughout the specification, the same reference numerals are used for the same or corresponding parts. Each feature of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will be apparent from and elucidated in connection with the following drawings, in which:

[0234] Figure 1 An example of the system of the present application is shown;

[0235] Figure 2 Examples of the transverse plane, RALP plane, LARP plane, and longitudinal plane of the present application are shown;

[0236] Figure 3 An example of determining the time point with the maximum acceleration is shown;

[0237] Figure 4A A flowchart example of a method for evaluating the vestibular system function of a subject is shown;

[0238] Figure 4B Another flowchart example of a method for evaluating the vestibular system function of a subject is shown;

[0239] Figure 5 A flowchart example of a method for evaluating the vestibular system function of a subject, including a test protocol combination, is shown;

[0240] Figure 6 An example of calculating the average response rate is shown.

[0241] The further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that while the detailed description and the specific examples, which show preferred embodiments of the invention, are given by way of illustration only, for a person skilled in the art, other embodiments of the present invention will become apparent from the following detailed description. Detailed Description of the Invention

[0242] The following detailed description presented in conjunction with the drawings is used as a description of various different configurations. The detailed description includes specific details for providing a thorough understanding of multiple different concepts. However, it will be apparent to those skilled in the art that these concepts may be implemented without these specific details. Several aspects of the system and method are described by means of multiple different blocks, functional units, modules, elements, steps, processes, algorithms, etc. (collectively referred to as "elements"). Depending on a particular application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0243] Figure 1 An example of the system of the present application is shown. The system 1 may be adapted to evaluate the function of the vestibular system of a subject 2. 3

[0244] In Figure 1 it is shown that the system 1 may include an eye measurement device 3, a motion sensing device 4, a display device 5, a user input device 6, and a processing device PD.

[0245] The eye measurement device 3 may be configured to record the pupil position, velocity value, and / or acceleration value of at least one eye of the subject 2. For example, the eye measurement device 3 may include a recording device 3A such as a camera for recording the at least one eye of the subject 2. In Figure 1 it is shown that the recording device 3A is located only at one eye of the subject 2, but it is foreseeable that it may be located at any other position as long as it is configured to record the pupil position, velocity value, and / or acceleration value of one or both eyes of the subject 2. As Figure 1 shown in

[0246] The motion sensing device 4 may be configured to sense at least the motion and / or position of the head of the subject 2 and provide at least one motion signal representing the acceleration value and / or velocity value of the rotation of the head of the subject 2 in at least one plane. The motion sensing device 4 is shown to be located at the center / middle part of the eye measurement device 3, but may be located at any position of the eye measurement device 3, for example in a releasable manner. As an alternative, the motion sensing device 4 may be located on the head of the subject 2 using a connecting device such as a headband so that it is not dependent on the eye measurement device 3 fixed to the head of the subject 2. For example, the motion sensing device 4 may be an accelerometer. The motion sensing device 4 may include more than two accelerometers for sensing the motion and / or position of the head of the subject 2.

[0247] The display device 5 may be configured to display at least one image 7, which is exemplified in Figure 1 in the form of a Landolt C optotype. The image 7 may be characterized by a property, which may refer to one or more of the following: the orientation, size, position, or contrast of the image 7. In other words, the image 7 may be displayed towards the left, right, bottom, or top of the display device 5, or may be displayed in a varying size, may be located in the middle of the display device 5 or along one of the edges of the display device 5, or may be displayed with a varying contrast. The display device 5 may be, for example, a screen / monitor.

[0248] The user input device 6 can be configured to receive user input. The user input can be provided by the subject 2 or the user 8 of the system 1, where the user 8 can be a medical examiner / clinician. For example, the user input can be related to the subject 2's estimation of the characteristics of the image 7 presented on the display device 5. As an alternative or in addition, the user input can be related to controlling the processing device PD, for example, by sending instructions based on which the test protocol is executed, and / or enabling or disabling the processing device PD.

[0249] As Figure 1 shown, the system can further include an additional display device 9, which can be configured to present a user interface 10, for example, for the user 8 to follow and control the test protocol.

[0250] The processing device PD is shown connected to the eye measurement device 3 (and / or can be directly connected to the recording device 3A), the motion sensing device 4, the display device 5, and the user input device 6. In addition, the processing device PD can be connected to an additional display device 9 (such as a test screen). As shown by the dashed line, the connection 11 can be a wired or wireless connection. The connection 11 can extend through a receiving device RD, which can direct control signals / instructions to and obtain control signals / instructions from the processing device PD.

[0251] The processing device PD can be configured to execute at least one of a plurality of test protocols. For example, the test protocol can be initiated by the user 8 entering instructions (user input) via the user input device 6. Each test protocol can be stored in the storage device MD of the system 1. The user 8 can follow and control the execution of the test protocol on the user interface 10.

[0252] One of the multiple test protocols, especially the fvHIT test protocol, can include continuously analyzing the motion signals transmitted from the motion sensing device 4 to the analysis device AD of the processing device PD via the connection 11. Thus, the time point with the maximum acceleration value can be determined. In response to the determination of the time point, the display device 5 can present an image, for example, in the form of a Landolt C optotype, for a preset time interval starting from the determined time point. The characteristics of the image 7 can be set / determined by the processing device PD based on the test protocol. In response to viewing the presented image 7, the subject 2 (or alternatively, the user 8) can provide an input to the user input device 6 related to the subject 2's estimation of the characteristics of the image 7. For example, the characteristic can be related to the orientation of the image 7, in other words, in which direction the image 7 is oriented. As an example, it is shown that the image 7 can be mirrored 7A so that it can be oriented in the opposite direction. Possibly, when setting / determining the characteristics of the image 7, the user input that has been received can be considered.

[0253] The processing device PD (or the analysis device AD) can be configured to determine the correspondence between the characteristics of the image 7 and the subject 2's estimate of the characteristics of the image 7. The correspondence can refer to whether the actual characteristics and the estimated characteristics are similar. The correspondence can be determined and saved at multiple maximum acceleration values and can be considered when evaluating the vestibular system function of the subject 2. The determined correspondence and the maximum acceleration values can be presented to the user interface 10 and evaluated by the user 8 on the user interface 10.

[0254] As Figure 1 shown, the processing device PD, the analysis device AD, the storage device MD, and the receiving device RD can be assembled in the housing 12.

[0255] Figure 2 Examples of the transverse plane, the vertical plane, the RALP plane, and the LARP plane of the present application are shown.

[0256] Figure 2 The head of the subject 2 is shown as viewed from above. The vestibular system 13 at the left ear and the vestibular system 14 at the right ear are shown. The vestibular system 13 at the left ear includes the left anterior canal, the left horizontal canal, and the left posterior canal. The vestibular system 14 at the right ear includes the right anterior canal, the right horizontal canal, and the right posterior canal.

[0257] The motion sensing device 4 can be disposed at the forehead of the subject 2, for example, intersecting the vertical plane 18 that divides the head into a left part and a right part. The motion sensing device 4 can be configured to sense the movement and / or position of the head of the subject 2 and provide a motion signal representing the acceleration value and / or velocity value of the rotation of the head in at least one of the above-mentioned planes. In other words, the motion sensing device 4 can sense in which plane and / or at which speed / acceleration the user (not shown) moves / rotates the head of the subject 2. The aforementioned planes can be the transverse plane, the vertical plane, the RALP plane, and / or the LARP plane.

[0258] The transverse plane 15 can refer to the rotation of the head in the horizontal plane (perpendicular to the vertical plane 18). Generally, the head can be lowered forward by about 30 degrees because this optimally simulates the horizontal canals of each ear (which are a pair of coplanar canals), namely the left horizontal canal and the right horizontal canal.

[0259] The RALP plane 16 can refer to the rotation of the head in the direction that optimally simulates the pair of right anterior and left posterior coplanar canals. The RALP plane 16 can be located at an angle of 45° relative to the vertical plane 18.

[0260] The LARP plane 17 can refer to the rotation of the head in the direction that optimally simulates the pair of left anterior and right posterior coplanar canals. The LARP plane 17 can be located at an angle of 45° relative to the vertical plane 18.

[0261] Figure 3 An example of determining the time point with the maximum acceleration value is shown.

[0262] Figure 3 The curve shows an example of the rotation of the head of the subject in the transverse plane measured by the motion sensing device and provided as a motion signal. In this curve, the acceleration value (° / s 2 ) is shown as a function of time (ms) from the start to the end of the rotation. As shown in the figure, the acceleration value starts from 0° / s 2 Increases to about 4000° / s at time t1 2 Thereafter, the acceleration value decreases as the head speed decreases before finally stopping the movement at time t2.

[0263] Thus, when the processing device executes the fvHIT test protocol, the analysis device may continuously analyze the motion signal from the motion sensing device (which forms the basis of the curve) and determine the time point t1 with the maximum acceleration value. Due to the time delay from determining the time t1 to the actual presentation of the image by the display device, the analysis device may be configured to present a start signal in response to both the acceleration value and the velocity value exceeding the corresponding threshold value. The start (start) signal may be presented at a time point earlier than the time point with the maximum acceleration value. In other words, there is a time delay between the earlier time point and the time point with the maximum acceleration value. The time delay may be, for example, at least 20 ms, such as 30 ms.

[0264] In response to determining the time point t1, the display device may present an image characterized by a characteristic for a predetermined time interval Dt starting from time t1 until time t3. Thereafter, the image may disappear.

[0265] During the time that the image is presented, the subject has time to view the image and can thereafter provide user input in the form of an estimate of a characteristic of the image.

[0266] Figure 4A An example flowchart of a method for assessing vestibular system function in a subject is shown.

[0267] In particular, the method may be related to the fvHIT test protocol mentioned above. After being started (for example, by a user via a user input device), the test protocol may include the step of continuously analyzing a motion signal from a motion sensing device representing the acceleration of the rotation of the subject's head in at least one plane. The method may also include the step of determining a time point with a maximum acceleration value, at which time point an image characterized by a characteristic may be presented by a display device for a preset time interval starting from the determined time point with the maximum acceleration value. Thereafter, the method may include the step of receiving a user input including an estimate of the characteristic of the image via a user input device. Finally, the method may include the step of determining a correspondence between the characteristic and the estimate of the characteristic.

[0268] Figure 4B Another flowchart example showing an evaluation method for the vestibular system function of a subject is presented.

[0269] Compared to Figure 4A , Figure 4B the flowchart of may additionally include the step of analyzing that the device presents a start signal in response to both the acceleration value and the velocity value from the motion sensing device being determined to exceed the corresponding thresholds. Otherwise, the start signal will not be presented, but rather the acceleration value and the velocity value of the continuous motion signal will be analyzed.

[0270] Figure 5 A flowchart example showing an evaluation method for the vestibular system function of a subject, including a test protocol combination, is presented.

[0271] One advantage of configuring the system to execute a test protocol combination is to avoid duplication. In other words, if the DVA, GST, and fvHIT test protocols are to be executed on the same day, the results of the static DVA test protocol (which evaluates the smallest visual target that a subject can see with the head stationary) and the VPT test protocol (which determines the fastest visual target that a subject can recognize) can be copied (e.g., simultaneously) to each of the DVA, GST, and fvHIT test protocols.

[0272] Thus, it is not necessary to execute the static DVA and VPT test protocols before each of the DVA, GST, and fvHIT test protocols.

[0273] Another advantage of configuring the system to execute a test protocol combination is that all measured and analyzed data can be compared in a single report on the same day.

[0274] In Figure 5 the test protocol combination may include the vHIT test protocol, followed by the DVA test protocol and the GST test protocol, and finally the fvHIT test protocol.

[0275] After starting, the method may include: positioning the eye measurement device on the subject and performing an eye calibration measurement. Thereafter, the vHIT test protocol may be executed in the transverse plane, the RALP plane, and the LARP plane.

[0276] Subsequently, the motion sensing device can be placed on the subject's head (e.g., connected to the eye measurement device) and calibrated. Thereby, a DVA test protocol can be performed, which includes the steps of performing a static visual acuity measurement, i.e., determining the image size that the subject can clearly see with the head stationary, and then the steps of performing a visual processing time measurement (VPT test protocol). Finally, a DVA test can be performed, which can include moving the subject's head at 100° / s by the user and inputting the subject's estimate of the image until the minimum recognizable image threshold is reached for both horizontal and vertical plane movements.

[0277] After the DVA test protocol, a GST test protocol can be performed by the processing device, starting to receive the results of the static DVA and visual processing time measurements. Subsequently, a GST test can be performed, i.e., moving the subject's head at an increasing speed and inputting the subject's estimate of the image until measurements are performed for speed values above the threshold speed value in both the horizontal and vertical planes.

[0278] Finally, an fvHIT test protocol can be performed by the processing device, starting to receive the results of the static DVA test and visual processing time measurements. Subsequently, an fvHIT test can be performed, i.e., moving the subject's head at different accelerations and inputting the subject's estimate of the image (i.e., the characteristics of the image) in the horizontal plane, RALP plane, and LARP plane.

[0279] After the combined test protocol has been performed, the user can (e.g., using a user interface) evaluate the data obtained from the vHIT, DVA, GST, and fvHIT tests and generate a single report, which can be output (e.g., to a patient data server) for subsequent viewing.

[0280] Figure 6 An example of the calculation of the average response rate for horizontal movement in the fvHIT test protocol is shown.

[0281] In Figure 6 the left diagram shows the percentage of correct scores (of the subject's estimate of the image characteristics) as a function of head acceleration ° / s (divided into acceleration windows and right / left movement (i.e., for each acceleration window, the left bar represents left movement and the right bar represents right movement)).

[0282] The right diagram shows the correct response count as a function of head acceleration ° / s (divided into acceleration windows and right / left movement (i.e., for each acceleration window, the left bar represents left movement and the right bar represents right movement)).

[0283] When appropriately substituted by the corresponding processes, the structural features of the system described above, detailed in the "Detailed Description" and defined in the claims, can be combined with the steps of the method of the present invention.

[0284] Unless otherwise indicated, as used herein, the singular forms "a", "the" also include the plural (i.e., have the meaning of "at least one"). It should be further understood that the terms "having", "including" and / or "containing" as used in the specification indicate the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof. It should be understood that unless otherwise indicated, when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Unless otherwise indicated, the steps of any method disclosed herein do not have to be performed in the exact order disclosed.

[0285] The claims are not limited to the various aspects shown herein, but cover the full scope consistent with the claim language, where unless otherwise indicated, an element recited in the singular does not mean "one and only one" but rather "one or more". Unless otherwise indicated, the term "some" means one or more.

Claims

1. A system for evaluating vestibular system function of a subject, comprising: an eye measurement device configured to record pupil position, velocity value, and / or acceleration value of at least one eye of the subject; A motion sensing device configured to sense at least the motion and / or position of the subject's head and provide at least one motion signal representing an acceleration value and / or a velocity value of rotation of the subject's head in at least one plane; A display device configured to display at least one image; A user input device for receiving user input; a processing device connected to the eye measurement device, the motion sensing device, and the display device; The processing device is configured to execute at least one of a plurality of test protocols, wherein one of the test protocols comprises: - continuously analyzing at least one motion signal from the motion sensing device and determining the time point with the maximum acceleration value; - presenting an image characterized by a characteristic for a predetermined time interval starting from the determined time point with the maximum acceleration value by means of a display device; - receiving via a user input device a user input comprising an estimate of a characteristic of said image; Therein, the processing means is configured to determine a correspondence between the characteristic and the estimate.

2. The system according to claim 1, wherein: The display device is configured to display the at least one image such that the at least one image is visible to a subject, wherein the at least one image includes an optotype.

3. The system according to claim 1, wherein: The characteristic of the at least one image is related to the orientation, size, position, or contrast of the image.

4. The system according to claim 1, wherein: The step of continuously analyzing at least one motion signal from the motion sensing device and determining a time point having a maximum acceleration value comprises a processing device: - comparing the acceleration value of each of the at least one motion signal with a predetermined acceleration threshold value; - comparing a velocity value of each of the at least one motion signal with a predetermined velocity threshold; - presenting a start signal in response to both the acceleration value and the velocity value exceeding respective threshold values.

5. The system according to claim 4, wherein: The step of presenting an image characterized by a characteristic for a preset time interval starting from the determined time point with the maximum acceleration value through a display device comprises: - in response to said start signal being presented, presenting said image by means of a display device, wherein characteristics of said image are determined by the test protocol performed.

6. The system according to claim 1, wherein: The step of receiving, via a user input device, a user input comprising an estimate of a characteristic of said image comprises: -Receive a response from the subject or from a user of the system.

7. The system according to claim 1, wherein: The processing device is configured to score the percentage of correct estimates of the characteristic at different rotational accelerations of the subject's head in each corresponding plane.

8. The system according to claim 1, wherein: The processing means is configured to re-execute a particular test protocol in response to receiving an instruction in the form of user input via the user input means.

9. The system according to claim 1, wherein: The processing device is configured to execute a specific test protocol from among the plurality of test protocols in response to receiving an instruction to execute the specific test protocol from among the plurality of test protocols via the user input device.

10. The system according to claim 1, wherein: At least one plane includes a transverse plane, a right anterior and left posterior RALP plane, and / or a left anterior and right posterior LARP plane, wherein the transverse plane refers to the head rotation in the horizontal plane, the RALP plane refers to the head rotation in the direction that best simulates the right anterior and left posterior coplanar pair, and the LARP plane refers to the head rotation in the direction that best simulates the left anterior and right posterior coplanar pair.

11. The system according to claim 1, wherein: The motion sensing device is configured to be connected to the eye measurement device.

12. The system of claim 1, wherein: The display device includes a refresh rate of at least 240 Hz.

13. The system of claim 1, wherein: The user input device includes a remote control, a keyboard, or a touch screen.

14. The system of claim 1, wherein: The plurality of test protocols also includes a video head impulse test vHIT test protocol, a dynamic visual acuity DVA test protocol, and / or a gaze stabilization test GST test protocol.

15. The system of claim 1, wherein: The processing device is configured to determine the visual focus of the subject on the display device based on the recorded direction of at least one eye of the subject.

16. The system of claim 1, wherein: The eye measurement device comprises a camera for recording at least one eye of the subject.

17. A method for evaluating vestibular system function of a subject, the method comprising: Executing, by a processing device, at least one of a plurality of test protocols, wherein one of the test protocols comprises: - continuously analyzing at least one motion signal from the motion sensing device representing the rotational acceleration of the subject's head in at least one plane; - determining the point in time with the maximum acceleration value; - presenting, by means of a display device, an image characterized by a characteristic for a predetermined time interval starting from the determined time point with the maximum acceleration value; and - receiving via a user input device a user input comprising an estimate of a characteristic of said image; Therein, the method further comprises determining a correspondence between the characteristic and the estimate.

18. A data processing system comprising processing means and program code, the program code causing the processing means to execute at least some of the steps of the method according to claim 17.

19. A computer program product, comprising a computer program including instructions, which, when the computer program is executed by a system according to any one of claims 1 to 16, cause the system to perform the steps of the method according to claim 17.

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