Syntactic comprehension deficits are associated with MRI white matter alterations in dementia.

Comprehension difficulties associated with periventricular and deep white matter alterations (WMA) in mild dementia were investigated using portions of the Boston Diagnostic Aphasia Examination (BDAE) Complex Ideation subtest and Syntax subtests. Mild dementia participants were grouped according to the extent of their WMA as observed on magnetic resonance imaging (mild WMA n = 45 vs. moderate to severe WMA n = 52). Correlation and regression analyses also were performed to examine the link between WMA and comprehension abilities, as well as the link between comprehension abilities and neuropsychological measures of executive functioning, language, episodic memory, and overall dementia severity. Results showed that the WMA groups differed on the BDAE-Syntax subtests, with the severe WMA group demonstrating more impairment. Correlation and regression analyses including the entire sample also demonstrated that the extent of WMA was significantly linked to Syntax test scores but not Complex Ideation scores. Regression analyses including neuropsychological measures showed that the BDAE-Complex Ideation score was marginally predicted by only overall dementia severity, whereas the BDAE-Syntax scores were significantly predicted by independent measures of working memory/executive functioning. In conclusion, greater subcortical WMA and executive deficits are associated with greater difficulties in syntactic comprehension in individuals with mild dementia.

Neuropsychological functioning of dementia patients with psychosis.

The current research sought to test the hypothesis that psychotic symptoms in patients with dementia might be due to relatively greater executive control and visuoperceptual deficits. Twenty-four dementia patients with psychosis and 24 outpatients without psychosis diagnosed with either probable Alzheimer's disease (AD) or possible/probable Ischemic Vascular Dementia (IVD) were studied. Groups did not differ with respect to age, education, severity of dementia, or depression. Presence and severity of psychosis was measured with a modification of the Neuropsychiatric Inventory (NPI; Cummings, J. L., Mega, M., Gray, K., Rosenberg-Thompson, S., Carusi, D. A., & Gorbein, J. (1994). The neuropsychiatric inventory: Comprehensive assessment of psychopathology in dementia. Neurology, 44, 2308-2314). Between-group and regression analyses found a consistent relationship such that patients with psychosis obtained low scores on the Boston Revision Wechsler Memory Scale-Mental Control subtest (WMS-MC subtest), a test of executive control. On some analyses patients with psychosis also made more perceptual errors on tests of naming and obtained higher scores on tests of delayed recognition memory. However, the relationship between severity of psychosis and performance on visuoperceptual and memory measures was considerably less robust. These data suggest a strong relationship between severity of psychosis and poor performance on executive control. Less evidence was obtained to support our contention that psychotic symptoms in dementia may arise from an interaction of neuropsychological deficits involving greater impairment in executive and visuoperceptual functioning.