In an ageing society, it is necessary to detect the cognitive decline of individuals at an early stage using simple measurement methods, thus enabling early health care for those affected. Older adults show reduced motor skills, which is attributed to three factors: Decrease in central and peripheral sensorimotor functions, decrease in information processing and/or changes in the motor system. Therefore, older subjects sometimes show pauses in movements (inter-segment intervals / ISI), which consist of individual movement segments. ISIs are generally longer or more variable when participants' motor control or planning is reduced. Therefore, measuring ISIs during target movements is a useful measure for assessing human movement control. Good motor planning is characterised by short movement durations and short ISIs, while reduced motor planning ability (as in participants with mild cognitive impairment / MCI or dementia) is characterised by longer movement durations and/or ISIs.
Overall, the study showed that MCI participants needed significantly more time to draw than cognitively healthy participants. MCI men had significantly longer ISIs than non-MCI men. This difference was not found in women. Based on the ISI, a simple classifier could be developed that correctly classified 63% of the men. By adding the tapping behaviour (see Kutz et al 2022), the classification can be improved to 80%. For the construction of an ideal classifier, the age-related degeneration of the cortical and subcortical motor areas must be considered. Therefore, an individualised analysis of movement performance in old-old subjects is necessary. You'll find the full length paper here