Diagnostic data providing method

Abstract

To provide a diagnostic data providing method capable of easily providing diagnostic data for evaluating and diagnosing a degree of progression of mild dementia and Alzheimer's disease.SOLUTION: A diagnostic data providing method includes the steps of: filtering a somatosensory evoked potential of a subject with a band-pass filter including at least a portion of 400 to 1000 Hz in a pass band to obtain a high-frequency vibration potential; selecting a peak P1 whose peak top time is closest to a time T1 at which the somatosensory evoked potential exhibits a maximum magnitude A1 (μV) out of a plurality of peaks in the high-frequency vibration potential; and calculating a ratio between the maximum magnitude A1 (μV) and a magnitude A2 (μV) of the peak P1 to obtain diagnostic data including the ratio.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for providing diagnostic data for diagnosing mild dementia, Alzheimer's disease, and the like. [Background technology]

[0002] Since early treatment of Alzheimer's disease can slow the progression of the disease, early diagnosis is desirable. Known methods for diagnosing Alzheimer's disease include a method for measuring the degree of brain atrophy using MRI images (VSRAD). For example, Patent Document 1 discloses an image diagnosis support system that utilizes MRI images. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-180929 Summary of the Invention [Problem to be solved by the invention]

[0004] However, MRI scans are expensive and only a limited number of medical institutions offer them, so there is a need for a simpler method to assess and diagnose the progression of Alzheimer's disease.

[0005] Therefore, an object of the present disclosure is to provide a method for providing diagnostic data that can easily provide diagnostic data for evaluating and diagnosing the degree of progression of mild dementia and Alzheimer's disease. [Means for solving the problem]

[0006] The present disclosure relates to, for example, the following [1] to [3]. [1] A step of filtering the subject's somatosensory evoked potential with a bandpass filter whose passband includes at least a portion of 400 to 1000 Hz to obtain a high-frequency oscillatory potential; selecting a peak P1 from among the plurality of peaks in the high-frequency oscillatory potential, the peak P1 having a peak top time closest to a time T1 at which the somatosensory evoked potential exhibits a maximum amplitude A1 (μV); calculating a ratio between the maximum amplitude A1 (μV) and the amplitude A2 (μV) of the peak P1, and obtaining diagnostic data containing the ratio; Including, How to provide diagnostic data. [2] The method of providing described in [1], wherein the ratio is A2 / A1, the ratio of the amplitude A2 (μV) to the maximum amplitude A1 (μV). [3] The method of providing according to [1] or [2], wherein the diagnostic data is diagnostic data for at least one type selected from the group consisting of mild dementia and Alzheimer's disease. [Effects of the Invention]

[0007] According to the present disclosure, a method for providing diagnostic data is provided that can easily provide diagnostic data for evaluating and diagnosing the degree of progression of mild dementia and Alzheimer's disease. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a somatosensory evoked potential. [Figure 2] FIG. 10 is a diagram showing an example of a high-frequency oscillating potential. [Figure 3] FIG. 1 is a diagram showing the relationship between the ratio A1 / A2 and the VSRAD score. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will be described in detail below.

[0010] The method for providing diagnostic data of this embodiment includes the steps of: filtering the subject's somatosensory evoked potential with a bandpass filter whose passband includes at least a portion of 400 to 1000 Hz to obtain a high-frequency oscillatory potential (hereinafter also referred to as the first step); selecting, from among multiple peaks in the high-frequency oscillatory potential, peak P1 whose peak top time is closest to time T1 at which the somatosensory evoked potential shows maximum amplitude A1 (μV) (hereinafter also referred to as the second step); and calculating the ratio between maximum amplitude A1 (μV) and the amplitude A2 (μV) of peak P1 to obtain diagnostic data containing the ratio (hereinafter also referred to as the third step).

[0011] The present inventors have found that the ratio of the maximum amplitude A1 of the somatosensory evoked potential to the amplitude A2 of a predetermined peak P1 of the high-frequency oscillatory potential shows a good correlation with the degree of progression of Alzheimer's disease, more specifically, the atrophy rate of the parahippocampal gyrus in VSRAD. That is, according to the method for providing diagnostic data of this embodiment, it is possible to easily provide diagnostic data for evaluating and diagnosing the degree of progression of mild dementia and Alzheimer's disease based on the somatosensory evoked potential and the high-frequency oscillatory potential.

[0012] Furthermore, somatosensory evoked potentials can be measured more easily using less expensive equipment than MRI examinations, and more medical institutions are able to perform the examinations. Furthermore, high-frequency oscillatory potentials are obtained by filtering somatosensory evoked potentials with a bandpass filter that includes at least a portion of the 400 to 1000 Hz frequency band, and can be easily obtained from somatosensory evoked potentials. In other words, the method provided by this embodiment can provide diagnostic data for assessing and diagnosing the progression of mild dementia and Alzheimer's disease using a test that is simpler than MRI examinations.

[0013] The first step is a step of obtaining a high-frequency oscillatory potential by filtering the somatosensory evoked potential of the subject with a bandpass filter whose passband includes at least a part of 400 to 1000 Hz.

[0014] The subject may be, for example, a patient with mild dementia or a patient with Alzheimer's disease. In patients with mild dementia and patients with Alzheimer's disease, the correlation between the ratio and the VSRAD score tends to be more pronounced.

[0015] Somatosensory evoked potentials (SEPs) are recorded potentials evoked by electrical stimulation of peripheral nerves.

[0016] The method for measuring the somatosensory evoked potential is not particularly limited and may be a known method. The somatosensory evoked potential may be measured, for example, by the method and conditions described below.

[0017] High-frequency oscillations (HFOs) are obtained by filtering the somatosensory evoked potentials with a bandpass filter whose passband includes at least a portion of 400 to 1000 Hz. The passband of the bandpass filter may be, for example, 400 to 1000 Hz.

[0018] The filtering of the somatosensory evoked potential may be performed by a known method, and the filtering of the somatosensory evoked potential may be measured, for example, by the method and conditions described below.

[0019] (acquisition of somatosensory evoked potentials) The device can be a general-purpose evoked potential measurement device. A stimulating electrode is attached to the palmar side of either the left or right wrist (directly above the median nerve). A recording electrode is attached to the contralateral skull (directly above the somatosensory cortex), and a reference electrode is attached between the eyebrows. Electrical stimulation is initiated from the stimulating electrode, and the waveform triggered by the stimulation is recorded. The stimulation conditions are 5 Hz, and the stimulation intensity is the maximum that the subject can tolerate. 1,000 additions are made to obtain a summed waveform triggered by the stimulation time.

[0020] (Acquisition of high frequency oscillatory potential) The amplitude of the peak N20 (a large waveform observed with a latency of approximately 20 msec after stimulation) is measured from the raw waveform of the somatosensory evoked potential. Next, a bandpass filter (400-1000 Hz) built into the device is applied to extract the waveform of the high-frequency oscillatory potential. Details are as described in the Examples.

[0021] Fig. 1 is a diagram showing an example of a somatosensory evoked potential, and Fig. 2 is a diagram showing an example of a high-frequency oscillatory potential.

[0022] The second step is to select a predetermined peak P1 from the multiple peaks in the high-frequency oscillatory potential. The high-frequency oscillatory potential has multiple peaks with different peak-top times, and peak P1 is the peak whose peak-top time is closest to time T1 when the somatosensory evoked potential shows a maximum amplitude A1 (μV).

[0023] The third step is to calculate the ratio between the maximum amplitude A1 (μV) of the somatosensory evoked potential and the amplitude A2 (μV) of the peak P1 selected in the second step, and obtain diagnostic data containing this ratio.

[0024] The diagnostic data obtained in the third step may include a ratio A2 / A1 of the amplitude A2 (μV) to the maximum amplitude A1 (μV).The diagnostic data obtained in the third step may include a ratio A1 / A2 of the maximum amplitude A1 (μV) to the amplitude A2 (μV).

[0025] The diagnostic data provided by the method of the present embodiment can be suitably used as data for evaluating and diagnosing the degree of progression of mild dementia and Alzheimer's disease.

[0026] The diagnostic data provided by the method of this embodiment may be combined with other diagnostic data, such as the Mini-Mental State Examination (MMSE) score, to more accurately evaluate and diagnose the progression of mild dementia and Alzheimer's disease.

[0027] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. [Example]

[0028] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0029] Somatosensory evoked potentials and high-frequency oscillatory potentials were measured in multiple Alzheimer's disease patients using the following methods. (acquisition of somatosensory evoked potentials) 1. The subject lies supine on a bed and is asked to rest. The somatosensory evoked potential is measured using the program installed in the measuring device. 2. Place a stimulation electrode on the palmar side of the subject's right wrist, approximately 3 cm proximal to the wrist. 3. Place the recording electrode on the parietal side of the line connecting the top of the head and the earlobe, dividing it into thirds (C3), or 2 cm occipital from there. 4. Place the reference electrode between the eyebrows. 5. To determine the stimulation intensity, the range of stimulation intensity is examined in which the waveform is recorded stably and the subject does not feel any discomfort, and the maximum intensity within that range is used as the stimulation intensity. 6. Start recording. Stimulation is 5 Hz, and the stimulation intensity is the intensity calculated in step 6. 1000 additions are performed. A 0.5 Hz high-pass filter is applied during recording. 7. The recorded waveforms are averaged using the stimulation as a trigger to obtain the somatosensory evoked potential waveform. The latency and maximum amplitude of the waveform (N20) observed 20-30 ms after stimulation are measured.

[0030] (Acquisition of high frequency oscillatory potential) 1. When the built-in bandpass filter (400-1000H) is applied to the recorded somatosensory evoked potential waveform, a group of characteristic high-amplitude waveforms is extracted. These are high-frequency vibrations. 2. Identify the waveform observed at the time corresponding to the latency of N20 for the recorded high-frequency oscillation, and measure its latency and amplitude. If it is located between two waveforms, select the one with the closest latency. If it is located exactly at the midpoint, use the one with the largest amplitude.

[0031] The maximum amplitude A1 (μV) and the time T1 at which the maximum amplitude A1 was observed were determined for the somatosensory evoked potential. Furthermore, the peak P1 closest to the time T1 was selected from the multiple peaks in the high-frequency oscillatory potential, and its amplitude A2 (μV) was determined to calculate the ratio A2 / A1.

[0032] Figure 3 shows a graph with the subject's VSRAD score on the vertical axis and the ratio A2 / A1 (HFO / SEF in Figure 3) on the horizontal axis. As shown in Figure 3, there is a good correlation between the VSRAD score and the ratio A2 / A1, and it was confirmed that the ratio of maximum amplitude A1 to amplitude A2 (μV) is effective as diagnostic data for evaluating and diagnosing the degree of progression of mild dementia and Alzheimer's disease.

Claims

1. a step of filtering the subject's somatosensory evoked potentials with a bandpass filter having a passband including at least a portion of 400 to 1000 Hz to obtain high-frequency oscillatory potentials; The time when the peak top of the plurality of peaks in the high-frequency oscillatory potential is the time when the somatosensory evoked potential has a maximum amplitude A １ Time T indicating (μV) １ The peak P closest to １ and selecting The maximum amplitude A １ (μV) and the peak P １ Amplitude A ２ (μV) to obtain diagnostic data containing the ratio; Including, How to provide diagnostic data.

2. The ratio is the maximum amplitude A １ (μV) to the amplitude A ２ (μV) ratio A ２ / A １ The method of claim 1 , wherein

3. The method of providing according to claim 1 or 2, wherein the diagnostic data is diagnostic data for at least one type selected from the group consisting of mild dementia and Alzheimer's disease.

Images