Verbal learning patterns in moderate and severe traumatic brain injury.

Previous studies that have examined performances on the California Verbal Learning Test (CVLT) among individuals with traumatic brain injury (TBI) have found differing levels of performance. Differential patterns of performance, however, have only been inferred. The present investigation sought to determine empirically if differential patterns of performance could be discerned in a TBI sample of 65 subjects with CVLT variables. The CVLT variables were selected based on the instrument's factor structure. Cluster analysis yielded four distinct subtypes of brain-injured individuals. The Active subtype demonstrated impaired unassisted retrieval, but used active encoding strategies and showed relatively intact ability to store novel information. The Disorganized subtype demonstrated an inconsistent, haphazard learning style along with deficits in encoding. The Passive subtype was marked by an overreliance on a serial clustering strategy as well as impaired encoding and/or consolidation. The Deficient subtype was the most impaired of all groups, exhibiting a slowed rate of acquisition, passive learning style, and significant impairment in encoding. Implications for rehabilitation are discussed.