Central nervous mechanisms underlying effects of cognitive impairment on dual-task stance:functional near-infrared spectroscopy analysis
BACKGROUND:Elderly people with mild cognitive impairment experience a decline in postural control ability due to cognitive function decline,making them more prone to falls.The dual-task paradigm,which more closely mirrors daily life,is often used to assess postural control ability.However,previous dual-task studies on cognition and postural control in elderly people with mild cognitive impairment have mainly focused on the external manifestations of postural control,with direct evidence of central nervous mechanisms still lacking.OBJECTIVE:To investigate the activation characteristics of the cerebral somatic sensorimotor cortex in the elderly people with mild cognitive impairment while performing the dual task of stance postural control and spatial working memory.METHODS:Participants were screened using the Montreal Cognitive Assessment,enrolling 16 elderly people with mild cognitive impairment and 17 healthy older people.They performed five task tests:spatial working memory,dual-feet balance stance,Romberg stance,dual task of dual-feet balance stance and spatial working memory,and dual task of Romberg stance and spatial working memory.Functional near-infrared spectroscopy and a three-dimentional force platform were used simultaneously to collect data on cerebral cortex(20 channels)hemodynamics and center of pressure swing trajectory.RESULTS AND CONCLUSION:In Romberg stance,dual task of dual-feet balance stance and spatial working memory,and dual task of Romberg stance and spatial working memory tasks,center of pressure displacements in anterior-posterior and medial-lateral directions were significantly greater in mild cognitive impairment elderly people than that in normal elder people(P<0.05).In dual task of dual-feet balance stance and spatial working memory task,ΔHbO2 at channel 15(right pre-motor cortex and supplementary motor area)was significantly greater in mild cognitive impairment elderly people than that in normal elder people(P<0.05).In dual task of Romberg stance and spatial working memory task,ΔHbO2 at channels 15 and 17(right pre-motor cortex and supplementary motor area)was significantly greater in the elderly people with mild cognitive impairment compared with the healthy older people(P<0.05).In dual task of Romberg stance and spatial working memory task,a significantly positive correlation in the elderly people with mild cognitive impairment(r=0.659,P<0.05)and a strong positive correlation in the healthy older people were observed between center of pressure displacement in medial-lateral direction and ΔHbO2 at channel 15(r=0.840,P<0.05).The results indicate that compared with the cognitively normal healthy older people,the elderly people with mild cognitive impairment showed weaker stance postural control capability during the dual task of stance postural control and spatial working memory,with higher activation levels in the right pre-motor cortex and supplementary motor area.The increased brain resource allocation for lateral postural control may represent the brain compensation mechanism in the elderly people with mild cognitive impairment due to cognitive decline leading to weakened stance postural control ability.
mild cognitive impairmentpostural controlspatial working memorypre-motor cortexsupplementary motor areafunctional near-infrared spectroscopy
万方数据
维普
