The presence and predictive value of astereognosis and agraphesthesia in patients with Alzheimer's disease.

Sensory and motor functions are good markers of neurocognitive decline due to their proximity and hierarchical relationship to high-order processes. The current study investigated if patients with Alzheimer's disease (AD) differed from a healthy control group in two tactile perceptual processes: astereognosis and agraphesthesia. Analyses were also conducted to see if these tactile processes were predictive of higher-order cognitive functioning. Twenty-eight patients with AD (mean age = 75.86) were compared to 28 healthy control subjects (mean age = 76.38) and were administered the Dean-Woodcock Sensory Motor Battery and the Woodcock-Johnson Psychoeducational Battery-Revised. Results suggest the patients with AD demonstrated significantly higher levels of tactile disturbance and astereognosis while agraphesthesia was able to predict a substantial portion of the variance in 3/7 cognitive tests and 4/7 cognitive tests, respectively. This included measures of fluid reasoning, visual processing, crystallized language, short-term memory, and auditory processing. These results suggest that astereognosis and agraphesthesia may be good markers of the extent of cognitive impairment in AD and should be included in neuropsychological evaluations due to their functional importance.