Preoperative neuropsychological and behavioral evaluation of children with thalamic tumors

Functional involvement of the thalamus in cognitive processing has been only anecdotally reported in the literature, and these cases are mostly related to thalamic hemorrhages; there is no available information on cognitive development in children with thalamic tumors.

All children admitted with a diagnosis of thalamic tumor at the authors' institution between January 2008 and January 2011 were considered for the present study. Exclusion criteria were age less than 18 months and the presence of severe neurological deficits, both of which prevented a reliable neuropsychological evaluation. A complete preoperative neuropsychological evaluation was performed.

Twenty children were selected (mean age 102.4 months). Total IQ was in the normal range in all patients (mean 90.1, SD 13.87) with a significant difference between verbal IQ (mean 97.70, SD 17.77) and performance IQ (mean 84.82, SD 17.01). A significant correlation was found between global cognitive impairment and a histological finding of low-grade tumors (p < 0.001). Children with a mesial thalamic tumor had a higher working memory deficit and delayed recall disorders (p < 0.001). Naming disorders were related to the presence of a bilateral (p < 0.001) or mesial (p < 0.001) thalamic tumor, without a significant difference between left or right hemisphere involvement. A significant correlation was also found between the presence of neurolinguistic disorders and mesially located tumors (p < 0.001). Children with right-sided tumors more frequently had constructional apraxia and executive function disorders (p < 0.001).

The present study suggests that thalamic tumors in different locations might have specific neuropsychological profiles.