Method of manufacturing a portable critical flicker fusion measurement device

Abstract

A portable medical diagnostic device for early detection of neurodegenerative diseases comprises a processor, a communication interface and a display module. The processor receives instructions through the communication interface and controls the display module to generate visual stimuli with preset frequency changes according to the instructions, and the frequency changes are used for neurophysiological evaluation by measuring the critical flicker fusion (CFF) threshold. The present application realizes constant average brightness of visual stimuli by controlling the duty cycle of the light-emitting unit during frequency modulation, effectively eliminates brightness-induced visual artifacts, improves measurement accuracy, and uses digital logic to realize the mapping of frequency and visual symbols, simplifying the operation process.

Description

Technical Field

[0001] This invention relates to the field of medical diagnostic equipment and neurophysiological assessment tools, specifically to a portable, low-cost diagnostic device and method for early detection of neurodegenerative diseases based on critical scintillation fusion (CFF) threshold measurement. Background Technology

[0002] Early detection of neurodegenerative diseases, such as Alzheimer's disease (AD), is crucial for clinical intervention and effective management. Neurodegenerative diseases typically manifest as a progressive decline in cognitive and visual processing speed.

[0003] Critical flicker fusion (CFF) threshold is a widely accepted neurophysiological measure of these declines. The CFF threshold refers to the flicker frequency at which the human visual system perceives a modulated light source as stable, continuous illumination.

[0004] The neurophysiological basis of CFF perception primarily relies on the processing capacity of the central nervous system (CNS). The critical flicker fusion threshold (CFFT) represents the upper limit of the light flicker frequency that the visual system can resolve and is a key indicator of cortical arousal and alertness. Unlike static visual variables, CFFT is highly sensitive to neural processes at the cortical level, reflecting the brain's ability to process rapid temporal changes.

[0005] In clinical practice, a decrease in the cognitive function threshold (CFF) has been identified as an important biomarker for the progression of neurodegenerative diseases. Recent studies have shown that patients in the early and middle stages of Alzheimer's disease have significantly lower mean CFF values ​​compared to healthy controls. Furthermore, there is a strong positive correlation between CFF values ​​and standardized cognitive assessment scores (such as the Mini-Mental State Examination, MMSE), suggesting that CFF can serve as a non-invasive, objective, and cost-effective tool for the early detection of cognitive impairment.

[0006] However, existing CFF measurement tools typically face the following problems:

[0007] Cost and portability: Professional-grade laboratory equipment is usually expensive and bulky, making it difficult to achieve large-scale community screening or home monitoring;

[0008] Brightness stability: Many existing devices cannot effectively maintain a constant average brightness of visual stimuli during frequency modulation. Brightness fluctuations introduce visual artifacts and reduce the reliability of CFF threshold measurements;

[0009] Operational complexity: Existing equipment often lacks highly integrated digital control logic, making it difficult to achieve automated and standardized frequency scanning tests.

[0010] Therefore, developing a low-cost, high-precision, easy-to-operate portable CFF detection device with digital control capabilities to provide reliable, automated, and easily interpretable CFF measurement results is an urgent clinical need. Summary of the Invention

[0011] The purpose of this invention is to provide a portable medical diagnostic device that addresses the problems of high cost, poor portability, and unstable brightness control in existing CFF detection devices.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: a portable medical diagnostic device for early detection of neurodegenerative diseases, comprising a processor, a communication interface, and a display module. The processor receives instructions through the communication interface and controls the display module according to the instructions to generate visual stimuli with preset frequency changes, the frequency changes being used for neurophysiological assessment by measuring the critical flicker fusion (CFF) threshold.

[0013] A key technical feature of this invention is that the display module can perform frequency modulation while maintaining a constant average brightness of the visual stimulus by controlling the duty cycle or on / off cycle of the light-emitting units. This constant brightness control effectively eliminates brightness-induced visual artifacts and improves the reliability of CFF threshold measurement.

[0014] Furthermore, this invention achieves a one-to-one correspondence between frequency and visual symbols (such as numbers) through digital logic, which greatly simplifies user operation and improves the intuitiveness of testing. Attached Figure Description

[0015] Figure 1 This is a system architecture block diagram of the device described in this invention;

[0016] Figure 2 This is a flowchart illustrating the software control and modulation process of the device described in this invention.

[0017] Figure 3 This is a schematic diagram of the character layout on the LED matrix of the device described in this invention (taking the number "12" as an example).

[0018] Figure 4 This is a hardware connection schematic diagram of the device described in this invention. Detailed Implementation

[0019] Example 1 [Low-Cost Hardware Implementation Scheme]: In this example, the device adopts a highly integrated, low-cost architecture. The processor uses a microcontroller (such as the Arduino series or ESP32) with rich GPIO and PWM functions. The display module uses an 8x8 LED matrix and is controlled by an HT16K33 driver chip.

[0020] like Figure 1 As shown, the device connects the processor to the HT16K33 driver chip via an I2C bus. The driver chip manages the scanning and display of the LED matrix. The processor operates according to a set frequency. f (Hz) is used to calculate the onset time of the visual stimulus. T on and closing time T off .

[0021] like Figure 3 As shown, to improve intuitiveness, the device directly maps frequency values ​​to digital symbols using digital logic. For example, when the frequency is 12 Hz, the display module will present the number "12" on the matrix. This logic is implemented through a preset bitmap array, where the number "1" occupies the first column, the number "2" occupies the second column, and there are empty columns in between as separators to prevent misjudgment caused by visual persistence.

[0022] Example 2: [Frequency Modulation and Constant Brightness Logic]: In order to achieve high-precision CFF measurement, the device must maintain a constant average brightness when the frequency changes.

[0023] Let the target frequency be f In each cycle T = 1 / f Within the system, by adjusting the effective duration of pulse width modulation (PWM), the total luminous flux per unit time is kept consistent at different frequencies.

[0024] like Figure 2 As shown, the software flow is as follows:

[0025] Set target frequency f ;

[0026] Map the frequency to the corresponding digital bitmap;

[0027] Calculate the corresponding timing parameters ( T on , T off );

[0028] Execute a blinking cycle to achieve frequency modulation by rapidly switching display states;

[0029] Monitor user feedback to determine the CFF threshold.

[0030] Example 3 [Wireless and Automation Extension]: In an advanced implementation, the processor communicates with the mobile device via a built-in BLE or Wi-Fi module. The device supports an "Automated Frequency Ramp" mode, where the processor automatically and linearly increases the frequency from low to high until the user no longer perceives flicker, thereby achieving automatic threshold extraction without manual intervention.

Claims

1. A portable medical diagnostic device for early detection of neurodegenerative diseases, characterized in that, The device includes: processor; Communication interface; and The display module is used to generate a set of frequency-modulated visual stimuli. The processor receives user instructions through the communication interface and controls the display module to generate visual stimuli with preset frequency variations according to the instructions. The frequency variations are used for neurophysiological assessment by measuring the critical flicker fusion (CFF) threshold.

2. The portable medical diagnostic device for early detection of neurodegenerative diseases according to claim 1, characterized in that, The display module is configured to present a value corresponding to the modulation frequency through digital symbols (digits), wherein the digital symbols represent the value corresponding to the modulation frequency.

3. A portable medical diagnostic device for early detection of neurodegenerative diseases according to claim 1, characterized in that, The display module includes: A display array, the display array being composed of a plurality of light-emitting units; and A driving circuit, which is communicatively connected to the processor, is used to control the on and off of each light-emitting unit in the display array to present a graphic with a specific geometric shape on the display array, and the flashing frequency of the graphic corresponds to the preset frequency.

4. A portable medical diagnostic device for early detection of neurodegenerative diseases according to claim 3, characterized in that, The display array is an 8x8 LED matrix, and the driving circuit is an HT16K33 driver chip.

5. A portable medical diagnostic device for early detection of neurodegenerative diseases according to claim 3, characterized in that, The display module also includes a constant average brightness control unit, used to maintain a constant average brightness of visual stimuli when the display array is frequency modulated.

6. A portable medical diagnostic device for early detection of neurodegenerative diseases according to claim 1, characterized in that, The device also includes a wireless communication module, which is used to transmit the measured CFF threshold data to a remote medical terminal.

7. A method for early detection of neurodegenerative diseases based on the device of claim 1, characterized in that, Includes the following steps: The processor configures the display module to generate a set of visual stimuli with a preset frequency range. The flashing frequency of the visual stimulus is changed periodically by the display module; Obtain the user's perceptual feedback on the flicker frequency, and determine the critical flicker fusion (CFF) threshold of the visual stimulus based on the feedback; The CFF threshold is output and displayed as an early screening indicator for neurodegenerative diseases.

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