Motor performance is an ability to perform intended movements which occur in the motor cortex. Decline in motor performance is mainly due to aging and brain injuries. Brain-injured patients such as vascular dementia and stroke have decline in motor functions as main symptoms from the beginning stage of disease, thus patients can be screened by comparing force control capabilities with healthy people. The existing clinical testing methods, however, are subjective in terms of not using any quantitative measures. Therefore, quantitative analysis and in-depth understanding of normal motor performance is needed for screening of brain injury more precisely.
The present study is intended to analyze motor performance in healthy adults for the early screening of brain-injured patients. First, normal motor performances are analyzed by evaluating finger force control capabilities in healthy controls (30 males and females from each of 20s to 70s) identified by four movement phases which are initiation, development, maintenance, and termination. Initiation time (IT), development time (DT), maintenance error (ME), and termination time (TT) are measured to understand finger force control capabilities. As the result, IT, DT, ME, and TT of 70s had respectively 22%, 26%, 118%, and 31% higher than those of 20s ~ 30s. ME of female had significantly 36% higher than that of male.
Second, motor performances of brain-injured patients were compared with that of normal controls. Patients included three types of brain disorders, which are amnestic mild cognitive impairment (aMCI), subcortical vascular MCI (svMCI), and subcortical vascular dementia (SVD) in their 60s ~ 70s. Aforementioned measures of all patients had 1.1 ~3.4 times higher than those of normal controls. In particular, SVD patients were the most impaired in all phases among patients, and svMCI patients had 2.1 and 1.2 times more impaired than aMCI in maintenance and termination phase, respectively.
Lastly, force tracking evaluation protocol to analyze force tracking capabilities in normal controls (30 males and females from each of 20s to 70s) is developed. Composite sinusoidal wave considering two amplitudes (2 N, 4 N) and four frequencies (0.1 Hz, 0.2 Hz, 0.4 Hz, 0.8 Hz) was developed. Performances were evaluated by tracking real-time presented waveform as precisely as possible for 30 seconds. As the result, force tracking capabilities (time within the target range, TWR; root mean square error, RMSE; relative RMSE, rRMSE) were decreased in older adults, female, lower force level, and higher complexity conditions.