[P1–322]: DYSEXECUTIVE FUNCTION, DISINHIBITION AND APATHY AND THEIR CORRELATION WITH COGNITIVE DECLINE AND ALZHEIMER's DISEASE IN ADULTS WITH DOWN SYNDROME: PRELIMINARY RESULTS

There is evidence of a genetic association between Down syndrome (DS) and the early development of neuropathological features of Alzheimer's disease (AD). However, the onset of AD in such individuals is characterized by symptoms typical of early frontotemporal lobar degeneration, such as changes in personality and behaviour. Recent studies point to the fact that executive dysfunction, also related to frontal lobe circuits, precedes decline in memory in individuals with DS. In this study we examined the correlation of informant reports of changes in executive function, disinhibition and apathy with cognitive performance in individuals with DS over 30 years of age. For that scope we interviewed informants using the Frontal System Behavior Scale (FrSBe) and compared it with the participant's performances in an executive function assessment protocol developed by researchers from the University of Cambridge. In the FrSBe the higher the score the less adapted the behaviour. 47 participants with DS (mean age 41.9, range 30–61) were included in data analysis. Dementia diagnosis was based on ICD-10, DSM5 and DM-ID. Preclinical dementia was defined by declines in cognition or function that were higher than expectations with aging but of insufficient severity to be considered dementia. The subjects were divided into the following groups: 1) diagnosed with AD or preclinical dementia (N=13, 4 AD and 9 preclinical dementia); and 2) control group of healthy subjects (N=34). Age-controlled logistic regression showed significant differences between groups for all four variables of the FrSBe (apathy, disinhibition, executive function and total, p<0.01), in which patients had impaired performance. The cognitive performance of subjects was negatively correlated with the informant's report for the total FrSBe (Spearman's Rho = -0.701, p <0.001), for apathy (Spearman's Rho = -0.644, p <0.001) and for executive functions (Spearman's Rho = -0.703, p <0.001). Disinhibition did not reach a significant correlation with cognitive performance, however surprisingly; we found a significant difference between the groups for this item when comparing previous reports to cognitive decline (p=0.003). Preliminary data suggests that there is correlation between behavioural changes related to frontal lobe functioning, cognitive decline and dementia in people with DS.