Evaluation of visual hallucination based on pareidolia testing in patients with Alzheimer’s Disease

AIM: Pareidolia is a complex visual illusion that is considered as a marker of visual hallucinations. In this study, we aimed to measure pareidolic illusions with a simple experimental paradigm using the pareidolia test as an indicator of visual hallucination in the Alzheimer's Disease.
MATERIALS and METHODS: Thirty-four patients with Alzheimer's disease and 30 healthy subjects with no difference in age and sex were included in the study. The degree of cognitive impairment was determined by the Mini Mental State Examination and the MOCA test. 60 images is used as pareidolia test material including human face, some objects and artefacts. The patients' answers were divided into three groups as correct resoonse, illusory response and other response while test is scoring.
RESULTS: In this study, the correct response averages of healthy individuals were higher than the individuals in the patient group. Moreover, the mean number of illusory responses in the patients was 2.27 ± 3.42, whereas no illusory response was obtained in healthy subjects. There was no relationship between the number of illusory responses and the Mini Mental Test score, MOCA test score and duration of illness.
DISCUSSION and CONCLUSION: Pareidolia paradigm is a simple and useful test that reveals the tendency to subclinical visual hallucinations or hallucinations in patients with Alzheimer's disease.