Pattern of memory compromise in chronic geriatric schizophrenia, frontotemporal dementia and normal geriatric...

The purpose of this study was to explore whether memory deficits in schizophrenia are attributable to poor organisation/encoding during initial learning vs. memory decay.

Subjects included geriatric schizophrenia/schizoaffective disorders [SSD; n = 37; age = 59.92 (55-74); education = 11.70 (7-18)]; frontotemporal dementia [FTD; n = 41; age = 76.59 (64-83); education = 14.61 (12-20)] and geriatric controls [n = 107; age = 70.97 (55-93); education = 13.76 (6-20)]. Subjects were administered the Wechsler Memory Scale, Third Edition and discrepancy scores between immediate and delayed subtests/indices were used to explore possible differences between groups in pattern of impairment.

Significant differences were found between groups on age/education and these variables were related to several outcome measures. Gender was not related to diagnostic group and there were no gender differences on study variables. There were differences between the SSD subjects on several variables, with the schizoaffective subjects performing worse despite equivalence on global cognitive function, living status and chronicity. Seven one-way between-subjects ANCOVAs compared groups on discrepancy scores. RESULTS failed to suggest differences between groups on immediate-delayed memory discrepancy scores (p > 0.05). Subsequent analyses revealed differences in percentage retention scores between SSD and FTD on the faces subtest (p = 0.040), with SSD retaining greater information over time.

RESULTS failed to show distinctions between groups on pattern of memory impairment when using discrepancy comparisons. However, an analysis examining percentage retention scores revealed better maintenance of non-contextual visual information over time in SSD. Findings may suggest deficits in immediate encoding rather than memory decay for some types of memory ability among geriatric SSD. Our failure to document group differences when using discrepancy comparisons may be attributable to relative similarity in pattern between groups or the limited sensitivity of this technique.