Feasibility of a Web-based Survey of Hallucinations and Assessment of Visual Function in Patients with Parkinson’s Disease

Citation:

Jackson ML, Bex PJ, Ellison J, Wicks P, Wallis J. Feasibility of a Web-based Survey of Hallucinations and Assessment of Visual Function in Patients with Parkinson’s Disease. Interactive Journal of Medical Research. 2013;2(2):e30.

Abstract:

Background: Patients with Parkinson’s disease experience hallucinations, which may be related to decreased contrast sensitivity, i.e. the ability to discern shades of grey. Objective: To investigate if an online research platform can be used to survey patients with Parkinson’s disease regarding visual hallucinations and also used to assess visual contrast perception. Methods: Nine hundred and sixty four members of the online patient community, PatientsLikeMe, were invited via email to participate in this study. Participants completed a modified version of the University of Miami Parkinson’s Disease Hallucinations Questionnaire and an online vision test. Results: Results: Two hundred and sixty nine members (28% of invited) completed the study: 153 of this group had Parkinson's disease (57% of completers) and 116 (43%) were non-Parkinson’s controls. Hallucinations were reported by 28 subjects (18%) of the Parkinson’s group (PD). Although 10 subjects (9%) in the control group reported experiencing hallucinations only two of those subjects actually described formed hallucinations. Participants with Parkinson’s disease and the control group showed relatively good contrast perception as measured with the online letter test (F(1, 265) = 3.28, MSE = .414 , etap² = .012, P = .07). People who reported hallucinations showed contrast sensitivity levels that did not differ from levels shown by people without hallucinations (F(1, 265) =1.23, MSE =.155, etap² = .005, P = .27 ) although there was a trend towards lower contrast sensitivity in hallucinators. Two hundred and sixty nine members (28% of invited) completed the study: 153 of this group had Parkinson's disease (57% of completers) and 116 (43%) were non-Parkinson’s controls. Hallucinations were reported by 18% of the Parkinson’s group (PD). Although 9% of the control group reported experiencing hallucinations only 20% of those subjects actually described formed hallucinations. Participants with Parkinson’s disease and the control group showed relatively good contrast perception as measured with the online letter test (F(1, 265) = 3.28, MSE = .414 , etap² = .012, P = .07). People who reported hallucinations showed contrast sensitivity levels that did not differ from levels shown by people without hallucinations (F(1, 265) =1.23, MSE =.155, etap² = .005, P = .27 ) although there was a trend towards lower contrast sensitivity in hallucinators. Conclusions: Although more patients with Parkinson’s disease reported visual hallucinations than the control group, the report of hallucinations by controls may indicate that online questionnaires regarding hallucinations needs to be more specific to accurately detect a true history of formed visual hallucinations. Multiple questions outlining the nature of the hallucinations are required. In a clinical interview the specific nature of the hallucination would be further refined to rule out a vague description that does not indicate a true, formed visual hallucination. Contrary to our hypothesis both groups showed relatively good contrast sensitivity, perhaps representing a ceiling effect or limitations of online testing conditions that are difficult to standardize. Steps can be taken in future trials to further standardize online visual function testing, to refine control group parameters and to take steps to rule out confounding variables such as co-morbid disease that could be associated with hallucinations. Contacting subjects via an online health social network is a novel, cost-effective l method of conducting vision research that allows large numbers of individuals to be contacted quickly, and refinement of questionnaires and visual function testing may allow more robust findings in future research.