Neuropsychological analysis of auditory verbal hallucinations

Recent neuropsychological studies have distinguished deficits in verbal working memory, verbal memory, and confrontation naming from other neuropsychological domains as specifically related to the severity of auditory verbal hallucinations (AVH) in schizophrenia (Gisselgard et al., 2014; Siddi et al., 2017). To extend this research, it was hypothesized that AVH severity would be related only to measures within the language domain and the test battery was augmented with the [CTOPP2 and COWAT…define?] to more comprehensively define the language processing functions most predictive of AVH. A neuropsychological test battery was administered to a group of adult patients diagnosed with schizophrenia and schizoaffective disorder (N = 30), who continued to experience AVH despite clinical treatment. Multiple regression analyses demonstrated that poorer performance on measures of verbal working memory and verbal immediate memory significantly predicted greater AVH severity. Going beyond the prior studies, it was also shown that greater impairment of semantic fluency and lesser impairment in delayed general memory were also significant predictors of AVH. Intellectual ability and executive functioning, considered as covariates, were not significant predictors and their inclusion in regression analyses did not affect the pattern of results. Lastly, when cognitive predictors were accounted for, a trend toward an effect of medication (assessed as olanzapine equivalents) emerged such that higher dose predicted less severe AVH. Taken together, better performance on measures of linguistic processes associated with verbal working memory, semantic fluency and verbal learning predicts less severe AVH, perhaps most consistent with limited capacity language processing models. The finding that better delayed memory predicted more severe AVH is consistent with AVH memory models suggesting that AVH are dependent upon information recalled from memory storage.