Frontal dysfunction contributes to the genesis of hallucinations in non-demented Parkinsonian patients.
BACKGROUND
Hallucinations occur in patients with Parkinson's disease (PD) with reported prevalence ranging from 8% to 40%. Hallucinations are significantly associated with dementia in PD, but little is known about possible distinctive cognitive features of non-demented PD patients who develop hallucinations.


OBJECTIVE
The aim of the study was to assess selected cognitive abilities in non-demented PD patients with and without hallucinations in order to identify specific neuropsychological correlates of such phenomena.


METHODS
Forty-eight consecutive patients with PD and Mini Mental State Examination (MMSE) > or = 23 were examined for the presence of hallucinations and assessed on standardized neuropsychological tasks for semantic and phonological fluency, verbal learning and logical abstract thinking; disease severity was staged according to Hoehn and Yahr scale.


RESULTS
Fourteen (29.2%) of 48 patients experienced hallucinations. There was no difference between hallucinators and non-hallucinators on demographic variables, disease severity and dose of any pharmacological treatment. Disease duration was significantly longer in hallucinator vs non-hallucinator patients (p = 0.02). Patients with hallucinations scored significantly lower than patients without hallucinations only on verbal learning-immediate recall task (p = 0.0324), and semantic and phonological fluency tasks (p = 0.0005 and p = 0.0036, respectively).


CONCLUSIONS
Our results suggest that PD patients with hallucinations show reduced performance on tasks that explore executive functioning as compared with non-hallucinators. Therefore, executive dysfunction may be considered as a risk factor for the development of hallucinations in non-demented PD patients.
Grossi
Dario
D
Department of Psychology, Second University, Naples, Italy.
Trojano
Luigi
L
Pellecchia
Maria Teresa
MT
Amboni
Marianna
M
Fragassi
Nina Antonetta
NA
Barone
Paolo
P
D000368:Aged; D003072:Cognition Disorders / Q000523:psychology*; D003704:Dementia / Q000523:psychology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006212:Hallucinations / Q000209:etiology* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D012660:Semantics; D014706:Verbal Learning