Cognitive function determination method
Inventors
Yomota, Satoshi • Nakamura, Shin • Ando, Eiji • Asada, Takashi • Nakata, Hiroko • Uchida, Kazuhiko • Nishimura, Yoshinori
Assignees
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Publication Number
US-12263004-B2
Publication Date
2025-04-01
Expiration Date
Abstract
A cognitive function determination method includes applying a load including a sensory stimulus (5a) or tasks with different degrees of difficulty a plurality of times (S1), measuring a change in brain activity of a subject (P) when the load is applied and acquiring measurement data (S2), and determining a degree of cognitive function of the subject (P) (S3).
Core Innovation
The invention relates to a cognitive function determination method that applies a load including a sensory stimulus or tasks with different degrees of difficulty to a sensory body of a subject a plurality of times. An optical measurement device measures a change in brain activity of the subject when the load is applied, thereby acquiring measurement data comprising a plurality of change measurements. A processor determines a degree of cognitive function of the subject based on comparing the plurality of change measurements with one another.
A significant difference between a first change measurement and a second change measurement indicates that the subject is a non-demented person, and no significant difference indicates that the subject has cognitive impairment. In one form, an intensity of the sensory stimulus is increased each time the stimulus is applied regardless of a subject's response to any previously applied load. In another form, degrees of difficulty of the tasks are set such that a second task given after a first task is higher than the first task regardless of the subject's response.
The optical measurement is configured to measure brain activity changes using near-infrared spectroscopy, and the measured change corresponds to cerebral blood flow, including changes in oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin. Measurement sites are set within regions of the International 10-20 system, including F3, F4, P3, and P4, and the method leverages feature amounts derived from changes in cerebral blood flow across repetitions.
Claims Coverage
The document provides two independent claims. Both claims determine a degree of cognitive function by repeatedly applying a load, measuring optical brain-activity changes to obtain a plurality of change measurements, and comparing the measurements to decide non-demented versus cognitive impairment based on significant differences.
Comparing repeated sensory-stimulus change measurements for cognitive function degree
applying a load including a sensory stimulus to a sensory body of a subject a plurality of times; measuring, by an optical measurement device, a change in brain activity of the subject when the load is applied and acquiring measurement data comprising a plurality of change measurements; determining, by a processor, a degree of cognitive function based on comparing the plurality of change measurements with one another such that a significant difference between a first change measurement and a second change measurement indicates that the subject is a non-demented person and no significant difference indicates cognitive impairment.
Increasing sensory stimulus intensity each time regardless of response
an intensity of the sensory stimulus to be applied to the subject is increased each time the stimulus is applied regardless of a subject's response to any previously applied load when the change in brain activity is measured for determining the degree of cognitive function.
Comparing repeated task-load change measurements for cognitive function degree
applying a load including tasks with different degrees of difficulty to a subject a plurality of times; measuring, by an optical measurement device, a change in brain activity of the subject when the load is applied and acquiring measurement data comprising a plurality of change measurements; determining a degree of cognitive function based on comparing the plurality of change measurements with one another such that a significant difference between a first change measurement and a second change measurement indicates that the subject is a non-demented person and no significant difference indicates cognitive impairment.
Setting task difficulty to increase regardless of response
the degrees of difficulty of the tasks are set such that a second task given after a first task is higher than the first task regardless of a subject's response to the first task.
Across both independent claims, the core inventive concept is determining a cognitive function degree by repeatedly applying a load, measuring optical brain activity to obtain multiple change measurements, and classifying non-demented versus cognitive impairment based on significant differences versus no significant differences between measurements.
Stated Advantages
mitigates bias from individual familiarity/education by using repeatedly applied, intensity-increased stimulation when measuring brain activity changes
provides classification between non-demented persons and cognitive impairment based on significant differences among repeated change measurements
uses optical measurement, including near-infrared spectroscopy, as noninvasive measurement compared with MRI
Documented Applications
determining cognitive function degree to distinguish non-demented persons from persons having cognitive impairment, including mild cognitive impairment and Alzheimer’s patients as described
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