Frontal dysfunction contributes to the genesis of hallucination in non-demented Parkinsonian patients

Dario Grossi, Luigi Trojano, Maria Teresa Pellecchia, Marianna Amboni, Nina Antonetta Fragassi, Paolo Barone

Research output: Contribution to journalArticlepeer-review


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) ≥ 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.

Original languageEnglish
Pages (from-to)668-673
Number of pages6
JournalInternational Journal of Geriatric Psychiatry
Issue number7
Publication statusPublished - Jul 2005


  • Executive functions
  • Frontal lobe
  • Hallucinations
  • Parkinson's disease

ASJC Scopus subject areas

  • Geriatrics and Gerontology
  • Psychiatry and Mental health


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