Hand-oriented tasking assessment of fine movement control deficits in Alzheimer’s Disease

This study was designed to test the hypothesis that the patients with Alzheimer's disease (AD) may have deficits in their movement planning and execution of rapid target oriented arm movements. This exploratory study evaluated movement dynamics in grasping movements between AD and controls. Studies have used a paradigm in which the visual feedback of the object are different, this paradigm required subjects to grasp and lift with the index finger and the thumb a symmetrically shaped object. Eleven AD patients and age-matched controls participated in this work. Movement times, absolute distance errors, forces and force-rate profiles were analyzed. Results show a marked group effect on a subset of conditions, in particular when the patients could not rely on the visual feedback of hand movement. Our results support the hypothesis that the ability to recall and use visuo-spatial associations might underlie the impairment in complex motor behavior that has been reported in AD patients. Importantly, the sensory-motor deterioration (the declines in fine motor control and coordination) observed in the tasks of grasping, thus, could be used as an additional assessment tool in evaluating patients who might have MCI or AD. Quantifying the specific characteristics of motor performance in AD patients may help further our understanding of the possible mechanisms underlying the motor and cognitive deficits of AD.