The system has an electronic instrument (100) including a microprocessor to determine and transmit threshold walking speed value (K1) to an apparatus (A1). The apparatus includes a microprocessor (201), a data memory (203) and an indicator (202) to emit an audio and/or visual signal. A sensor (206) measures forward speed or displacement distance to deduce the forward speed. A program memory (204) includes a program (P10) to compare the measured forward speed with the threshold value and another program (P11) to emit a visual and/or sound signal based on the result of the comparison. An independent claim is also included for a method for detecting abnormal cognitive performance of an individual.
