Evaluation of the Addenbrooke's Cognitive Examination-III and its relationship with functional ability after traumatic brain injury.

Background: The Addenbrooke’s Cognitive Examination (ACE-III) was developed to offer a sensitive screening tool for dementia. Yet despite limited evidence to support its use, it is increasingly utilized within neurorehabilitation. Aim: Our aim was to explore whether the ACEIII norms provide sensitive cut-off values for assessment in community neurorehabilitation and examine how the ACE-III correlates with measures of functional impairment. Design, subjects and setting: This descriptive study included 49 traumatic brain injury (TBI) patients, 39 male, mean age 39.9years (SD=15.2), assessed within a community head injury service at a median of 13months (interquartile range (IQR)=20) post-injury. Method: Measures of test utility were performed on patient ACE-III data using predetermined cutoffs.1 Subsequent correlation analysis was carried out between ACE-III domains and equivalent Mayo-Portland Adaptability Inventory (MPAI-IV) scores, an established measure of functional ability after TBI.2 Results: Based on the cut-offs of 88/82, the ACEIII displayed a sensitivity of 0.59/0.42 and a false negative rate of 0.41/0.59 at the respective values. These findings of sensitivity are just above chance level and suggest that neither the low or high specificity cut-offs had sufficient predictive value in our TBI population. Further analysis specified a weak negative correlation between the ACE-III total scores and converted t-scores of the MPAI-IV abilities subcategory (r=–0.316, P<0.05), indicating better ACE-III scores are associated with greater functional abilities. However, subsequent non-parametric tests, despite showing appropriate directionality, found no significant correlations between the ACE-III cognitive domains and the equivalent MPAI-IV scores for attention (τ=–0.139, P=0.13), memory (τ=–.151, P=0.09), fluency (τ=–0.083, P=0.24), language (τ=– 0.105, P=0.18) and visuospatial skills (τ=–0.074, P=0.28). Thus, the relationship between ACE-III performance and functional abilities is not clear. Discussion: Our data suggest the ACE-III is not sensitive enough to be applied quantitatively in community neurorehabilitation. Yet as ACE-III performance is correlated with functional abilities, it may still be a useful qualitative measure in the neuropsychological evaluation of TBI patients. Conclusion: The ACE-III should not be applied as a quantitative measure in community neurorehabilitation unless further experimental research can demonstrate its utility in TBI. References 1. Hsieh S, Schubert S, Hoon C, et al. Validation of the Addenbrooke’s cognitive examination III in frontotemporal dementia and Alzheimer’s disease. Dement Geriatr Cogn Disord 2013; 36: 242–250. 2. Kean J, Malec JF, Altman IM, et al. Rasch measurement analysis of the mayo-Portland adaptability inventory in a community-based rehabilitation sample. J Neurotrauma 2011; 28: 745–753.