Olfactory identification and WAIS-R performance in deficit and nondeficit schizophrenia.
BACKGROUND
An expanding database supports the notion that the deficit syndrome (DS) is a discrete condition within schizophrenia and recent data argues that Smell Identification Deficits (SID) may have a primary relationship with its pathophysiology. If so, then the relationship of University of Pennsylvania Smell Identification Test (UPSIT) scores with other neurocognitive measures in DS patients may point to the neural substrate of the deficit syndrome.


METHODS
We examined the relationship of UPSIT scores and Wechsler Adult Intelligence Scale-Revised (WAIS-R) performance in 46 DSM-IV schizophrenia patients. The Schedule for the Deficit Syndrome (SDS) interview was used to subgroup the sample into 13 DS and 33 nondeficit syndrome (NDS) patients.


RESULTS
DS and NDS groups had similar mean ages, age of onset, and GAF scores, but DS patients had fewer years of education. DS and NDS patients also did not differ in full scale, verbal or performance IQ or in any WAIS-R subtest. However, UPSIT scores were significantly worse in the DS patients, most of whom met criteria for a clinically meaningful olfactory impairment. In DS patients, UPSIT scores were significantly correlated with Performance IQ, Block Design, and Object Assembly, all of which are associated with complex visual-motor organizational function thought to be mediated by parietal circuitry. UPSIT scores in NDS patients were significantly related with Vocabulary, Similarities, and Digit Symbol subtests, which are indicative of verbal functioning.


CONCLUSIONS
These preliminary data support previous findings suggesting that in addition to frontal neuropsychological abnormalities, DS patients may have greater performance impairments on tasks associated with parietal functioning. Our findings furthermore suggest that the parietal circuitry may be a conspicuous substrate for impaired odor identification ability in these patients. The lesser abnormalities in UPSIT ability in NDS patients may be attributed to verbal ability. These data are preliminary and further investigations with larger samples are needed to support our findings.
Seckinger
Regine Anna
RA
New York State Psychiatric Institute, Columbia University, New York, NY 10032, USA. regineanna@earthlink.net
Goudsmit
Nora
N
Coleman
Eliza
E
Harkavy-Friedman
Jill
J
Yale
Scott
S
Rosenfield
Paul J
PJ
Malaspina
Dolores
D
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D000857:Olfaction Disorders / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology*; D012044:Regression Analysis; D012559:Schizophrenia / Q000503:physiopathology*; D014888:Wechsler Scales