Reduction in manual asymmetry and decline in fine manual dexterity in right-handed older adults with mild cognitive impairment

Abstract

Research in Parkinson's or Alzheimer's disease suggests that hand function is affected by neurodegenerative diseases. However, little is known about the relationship between hand function and mild cognitive impairment (MCI). Therefore, we conducted a kinematic analysis of unimanual hand movements in MCI patients to answer whether manual asymmetries and manual dexterity are affected or preserved in this condition. Forty-one MCI patients and fifty healthy controls were tested with the Purdue Pegboard test. All participants were right-handed. Kinematic analyses (by hand) were calculated for path length, angle, and linear and angular velocities during reaching, grasping, transport and inserting. Group differences were tested by with factorial MANOVAs and laterality indexes (LI) were assessed. Groups were compared on "Right-Left" hand correlations to identify kinematics that best single-out patients. Kinematics from grasping and inserting were significantly more deteriorated in the MCI group, while outcomes for reaching and transport denoted superior performance. LIs data showed symmetry of movements in the MCI group, during reaching and transport. Comparisons of "Right-Left" hand correlations revealed that kinematics in reaching and transport were more symmetrical in patients. This study showed a deterioration of fine manual dexterity, an enhancement in gross dexterity of upper-limbs, and symmetrical movements in MCI patients.

Delayed and More Variable Unimanual and Bimanual Finger Tapping in Alzheimer’s Disease: Associations with Biomarkers and Applications for Classification

“…This gradual loss of asymmetry has been observed in MCI and AD previously and is independent of aging in general [ 29–31 ]. For example, compared to control subjects, MCI participants displayed more symmetric grasping and inserting movements on the Purdue Pegboard test [ 17 ], and AD subjects exhibited more similar finger tapping pace for both hands [ 32 ]. Considering handedness-related cortical morphological asymmetry (e.g., deeper central sulcal depth of the hemisphere controlling the dominant hand [ 33 ]), our observed pattern could potentially be explained by accelerated asymmetric cortical thinning that has been observed in AD [ 34 ].…”

“…Another study revealed that bimanual performance was more often affected than unimanual performance, especially when the bimanual test required the left and right fingers to operate alternating versus synchronous [ 15 ]. Changes in asymmetrical motor performance have been reported in MCI and AD before [ 17, 29–32 ] and may be related to lateralized differences in neural degeneration [ 33, 34 ]. Although there is some indication that deterioration of more complex motor function in AD is partly related to the cognitive dysfunction [ 35, 36 ], atrophy of motor brain regions such as the cerebellum suggests that primarily regression of core motor function underlies finger tapping degeneration [ 37–41 ].…”

Effects of home-based manual dexterity training on cognitive function among older adults: a randomized controlled trial

“…This corticomotoneuronal pathway is critical for individual finger movements and for grasping behaviors in primates, including humans [ 1 ]. Corresponding to this, a cross-sectional epidemiologic study indicated that hand use performance assessments, such as handgrip strength [ 9 ] and manual dexterity [ 2 ], are useful tools not only in estimating the status of cognitive function but also in screening for mild cognitive impairment status in early stages [ 10 , 14 , 15 ].…”