Visual symptoms in Parkinson disease (PD) may represent a spectrum from other visual symptoms (OvS) to visual misperceptions (VM) to visual hallucinations (VH), with progression of the latter associated with older age, duration of disease, presence of rapid eye movement (REM) sleep behavior disorder, cognitive impairment, and decreased gray-matter volume. This according to a recent study that aimed to determine whether PD patients with VH have different clinical characteristics and gray-matter volume than those with VM or OvS. Researchers conducted a retrospective chart review of 525 PD patients to identify the frequency of visual symptoms and the association with clinical and radiological features. They found:
- Among total PD cases, visual complaints were documented in 177 (33.7%).
- Among these, 83 (46.9%) had VH, 31 (17.5%) had VM, and 63 (35.6%) had OvS.
- When compared to OvS, patients with VH had significantly higher age, duration of disease, rate of REM sleep behavior disorder, and cognitive impairment.
- VH patients had decreased age-adjusted volumetric averages in 28/30 gray-matter regions when compared to PD without visual symptoms and 30/30 gray-matter regions when compared to VM patients.
Barrell K, Bureau B, Turcano P, et al. High-order visual processing, visual symptoms, and visual hallucinations: A possible symptomatic progression of Parkinson's disease. [Published online ahead of print November 27, 2018]. Front Neurol. doi:10.3389/fneur.2018.00999.