911 – Development of a psycho-sensory hallucinations scale in schizophrenia and parkinson's disease (PSAS scale)

Abstract

Although visual hallucinations in Parkinson's disease (PD) have been described in several major studies, little is known about over psycho-sensory hallucinations witch are hallmark symptoms of schizophrenia (SCZ). The purpose of this study was to to create and validate a specific tool for the assessment of all sensory modality of hallucinations in PD and SCZ.The Psycho- Sensory hAllucinations Scale (PSAS) was developed with sixteen items to evaluate the core aspect of hallucinations (‘guardian angel’; auditory, visual, olfactory and gustatory, cenesthetic modalities). It was then evaluated in patients with SCZ and idiopathic PD who met the hallucination criteria. Results 86 PD patients and 51 SCZ were evaluated by using the PSAS scale. Data from correlational analyses supported the construct and discriminant validity of the scale in all hallucinatory modalities were related to both gold-standard (PANSS P3 and UPDRS I Item2). Test-retest reliability (33 SCZ and 50 PD) over a 1-week interval determined 2 patients groups :stable : there's no significant (p>.05) differences between before and after measurements in each domainand unstable: all sub-scale and total score significantly (in the range .045 to .002) changed.Inter-rater reliability (18 SCZ and 17 PD) varied by subscale sense hallucinations and domain-specific κs ranged from .56 to .94. Conclusions The results suggest that the usefulness of PSAS as a clinical tool is for initial detailed evaluation and monitoring changes in hallucinations, in SCZ and PD. The next step will be to compare all modality hallucinatory manifestations in PD and schizophrenia.