Cognitive phenotypes in TBI

There are many different ways to categorize individuals with TBI in terms of clinical severity, mechanism of injury, and pathophysiology; each of which may impact prognosis and treatment (Hempill, 2013). The initial evaluation of individuals with TBI typically includes GCS, CT scan, and a neurologic exam (Saatman et al., 2008). However, the primary concern with these current diagnostic methods is that they lack specificity in terms of functional impairment and treatment selection. 

A possible solution to this problem could be to develop and implement a sub-classification system using cognitive taxonomies. This will allow for reliable clustering of individuals into meaningful groups, as seen in previous work with temporal lobe epilepsy and autism (Hermann et al., 2007, Tager-Flusberg et al., 2003; Losh et al., 2009). 

A taxonomic approach provides a common language among professionals within the field and facilitates refined investigations of both clinical and neurobiological correlates of TBI. Furthermore, taxonomies serve to improve the identification of appropriate treatment options. Limited research  on cognitive taxonomic classification in TBI has been conducted thus far. 

In a previous study, Goldstein et al. (2010) collected neuropsychological data from war veterans using the Halstead-Reitan and WAIS-R batteries. They observed that neuropsychological profiles were mainly heterogeneous and primarily linked to demographic variables. Using cluster analysis, they observed three categories (near normal, moderately impaired, and globally impaired). However, data was collected before 1997 and the neuropsychological tests used were outdated. In addition,  their sample was limited to a male veteran population. 

Thus, with more contemporary tests of cognitive domains and a diversified sample of individuals with TBI, we would possibly see increased heterogeneity and specificity of cognitive phenotypes.   

References:

Goldstein G, Allen DN, & Caponigro JM (2010). A retrospective study of heterogeneity in neurocognitive profiles associated with traumatic brain injury. Brain injury : [BI], 24 (4), 625-35 PMID: 20235765

Hermann B, Seidenberg M, Lee EJ, Chan F, & Rutecki P (2007). Cognitive phenotypes in temporal lobe epilepsy. Journal of the International Neuropsychological Society : JINS, 13 (1), 12-20 PMID: 17166299

Saatman KE, Duhaime AC, Bullock R, Maas AI, Valadka A, Manley GT, & Workshop Scientific Team and Advisory Panel Members (2008). Classification of traumatic brain injury for targeted therapies. Journal of neurotrauma, 25 (7), 719-38 PMID: 18627252

Tager-Flusberg H, & Joseph RM (2003). Identifying neurocognitive phenotypes in autism. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 358 (1430), 303-14 PMID: 12639328

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