A-073 Intra-Individual Variability in Stroke and Mixed Neurologic Conditions

Abstract

Abstract Objective Intra-individual variability (IIV) has shown utility in characterizing cognitive dysfunction in conditions including traumatic brain injury and dementia, but has been less studied in stroke. This study examined IIV in physical medicine and rehabilitation patients with stroke and mixed neurologic conditions. Method Participants (N = 95) were 40% female and 83% white with average age and education of 46 (SD = 13) and 14 (SD = 2) years, respectively. Participants completed an outpatient evaluation using a flexible battery of up to 33 common neuropsychological measures. Participants were grouped by diagnosis: stroke and other cerebrovascular events (e.g., aneurysm; 58%), and mixed neurologic conditions (e.g., anoxia, dementia; 42%). Adequate performance validity was determined on the basis of embedded and freestanding validity measures. Test battery scores were converted to T scores. Cases with four or more scores below 36 T were identified as impaired. Measures of IIV were calculated including overall test battery mean (OTBM), test battery standard deviation (SD), kurtosis, skew, range, and unbiased coefficient of variation (UCV). Groups were compared on IIV measures and impairment. Results Diagnostic groups were not significantly different on IIV measures. Impairment rates were not different in stroke (78%) and mixed (68%) groups. Unimpaired cases showed significantly higher OTBM, and significantly lower SD, range, and UCV (all p’s < .01); kurtosis and skew were not significantly different. Conclusions IIV markers of cognitive dysfunction in stroke are similar to those observed in dementia and other neurologic conditions. Further study of the clinical application of IIV measures is needed.