Executive clock drawing correlates with performance-based functional status in people with combat-related mild traumatic brain injury and comorbid posttraumatic stress disorder

Abstract

Executive Clock Drawing Tasks (CLOX parts 1 and 2) can predict functional impairment. This study determined the correlation between CLOX and other psychometric screening instruments with the Structured Assessment of Independent Living Skills (SAILS)-defined performance-based functional status in people with combat-related mild traumatic brain injury (TBI) and comorbid posttraumatic stress disorder (PTSD). We hypothesized that CLOX would correlate significantly with functional performance. This prospective, cross-sectional study design determined the correlation between a structured neuropsychological battery and functional status assessment. We calculated Pearson correlation coefficients between neuropsychological instruments and functional status scores. We entered neuropsychological measures correlating p < 0.1 with functional status into a linear regression model to determine independent contributions. Fifteen Operation Iraqi Freedom veterans participated. Only CLOX1 correlated significantly with functional competency and efficiency. Only mean CLOX1 scores were significantly lower in those scoring below the median for SAILS competency and in those scoring above the median for SAILS efficiency. CLOX1 contributed significant variance to functional status independent of mood or anxiety symptoms and was not affected by age or time since injury. Executive dysfunction per the brief, easily administered CLOX1 is sensitive to functional status following combat-related mild TBI, independent of PTSD anxiety with or without depression.