Reaction Time is a Marker of Early Cognitive and Behavioral Alterations in Pure Cerebral Small Vessel Disease.

BACKGROUND

The assessment of early and subtle cognitive and behavioral effects of cerebral small vessel disease (SVD) requires specific and long-lasting evaluations performed by experienced neuropsychologists. Simpler tools would be helpful for daily clinical practice.

OBJECTIVE

To determine whether a simple reaction time task that lasts 5 minutes and can be performed without external supervision on any tablet or laptop can be used as a proxy of early cognitive and behavioral alterations in CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), a monogenic form of pure SVD related to NOTCH3 mutations.

METHODS

Twenty-two genetically confirmed patients with CADASIL having preserved global cognitive abilities and without disability (MMSE >24 and modified Rankin's scale ≤1) were compared to 29 age-and-gender matched controls to determine group differences according to: 1) conventional neuropsychological and behavioral testing; 2) a computerized battery evaluating reaction time, processing speed, and executive functions. In a second step, correlations between reaction time and cognitive and behavioral alterations detected using both conventional and computerized testing were tested in patients.

RESULTS

Reaction time was significantly higher in patients than in controls (mean in patients: 283 ms - in controls: 254 ms, p = 0.03). In patients, reaction time was significantly associated with conventional and chronometric tests of executive functions, working memory, and apathy.

CONCLUSION

Reaction time obtained using a very simple task may serve as a proxy of early cognitive and behavioral alterations in SVD and could be easily used in daily clinical practice.