Two-year longitudinal follow-up of visual illusions and hallucinations in Parkinson’s disease

Exploring the Spectrum of Visual Illusions and Other Minor Hallucinations in Patients with Parkinson’s Disease in Lithuania

“…Furthermore, it has been suggested that certain phenotypic subtypes of PD may have a higher occurrence of minor hallucinations, as supported by a study that found a greater incidence of minor hallucinations, particularly visual illusions, in patients with the postural instability gait difficulty phenotype compared with the tremor-dominant phenotype; however, it is important to note that this finding could have been influenced by confounding factors, since the postural instability gait difficulty phenotype was also associated with more severe motor and other non-motor symptoms, as well as higher LEDD [19]. Regarding the clinical course, insufficient data are available to state that minor hallucinations independently increase the risk of developing visual hallucinations; while some studies suggest a close association between these phenomena, showing that minor hallucinations (including visual illusions) usually precede visual hallucinations and may even represent their milder form, others have shown that only a small proportion of PD patients with visual illusions evolve towards visual hallucinations over 2 years [20,21]. Functional magnetic resonance imaging studies have suggested that dorsal attention network dysfunction may be a key factor in the progression from minor hallucinations to well-structured visual hallucinations [22].…”