This study estimates the influence of schizophrenic formal thought disorders on cognitive functioning as revealed by the Luria-Nebraska (LN) neuropsychological assessment. Forty chronic schizophrenic patients were selected according to...
moreThis study estimates the influence of schizophrenic formal thought disorders on
cognitive functioning as revealed by the Luria-Nebraska (LN) neuropsychological assessment.
Forty chronic schizophrenic patients were selected according to DSMIV. Twenty patients with
severe formal thought disorders (+FTDs) were matched for age, sex, education, WAIS-IQ,
chronicity, dosage, and hospital care with twenty schizophrenics chosen for absence or mild
formal thought disorders (-FTDs). All subjects were administered the LN neuropsychological
battery. Twelve out of 14 scales of the LN were sensitive to FTDs while most LN scales were not
sensitive to severity of non-FTDs symptoms as measured by Andreasen's index. Discriminant
function analysis of the LN results, correctly classified 95% of patients from normals, and 85%
of -FTD and +FTD patients from the schizophrenic sample. The +FTD patients were significantly
poorer on measures of sensori-motor and fronto-temporal functioning. The -FTD patients scored
poorly on measures of fronto-basal functioning. Almost identical results were obtained when
possible confounding effects of severity of other psychotic symptoms were removed through
covariate procedures. Results support the association of FTD with neuropsychological deficits
independently of severity of other psychotic symptoms
