Minor visual phenomena (MVP), such as visual illusions, pareidolias, feeling of presence, and passage hallucinations, are often experienced by patients with Lewy Body Disease (LBD), in addition to complex visual hallucinations (VH), even in the early stages of the disease. This systematic review aimed to provide an up-to-date literature review of the occurrence and prevalence of MVP in LBD and to assess their potential associations both with VH and visuoperceptual and visuospatial deficits. A systematic literature search was carried out in PubMed, Web of Science, APA PsycInfo, Scopus, and Cochrane Library, and a total of 44 articles were included. The included studies showed significant variability in the occurrence of MVP in the LBD population and in the assessment methods used, such as standardized scales (e.g., the noise pareidolia test), semi-structured interviews (e.g., the North-East Visual Hallucinations Interview), and clinical descriptions. Similarly to VH, MVP appears to be highly specific to LBD, helping in differential diagnosis from Alzheimer’s Disease. The overall relationship between MVP, VH, and visuoperceptual/visuospatial deficits remains unclear. Some studies found that MVP (especially pareidolic responses and presence of hallucinations) was positively correlated with VH, yet it is challenging to determine whether MVP can be considered a precursor of future VH development. Negative associations were reported between MVP (especially pareidolias) and visuoperceptual/visuospatial abilities. However, it is not clear whether these deficits serve as independent, exclusive factors in MVP occurrence or if they interact with VH as a contributing component. Gaining insight into the occurrence of these phenomena could prove beneficial for differential diagnosis, prognosis, and prediction of treatment outcomes in patients with LBD.

Background/Objectives: Impairment in self-awareness (ISA) is one of the common consequences of an acquired brain injury (ABI) and is associated with anosodiaphoria. Collectively, these co-occurring neuropsychological disorders pose significant obstacles in the neurorehabilitation of moderate-to-severe ABI patients. Individuals who recover from ISA may present with anxiety and/or depression as adaptive reactions to the ABI, along with related functional disabilities. The present study investigated whether the level of metacognitive self-awareness (SA) is associated with the presence of anxiety and depression, apathy, or anosodiaphoria in patients with moderate-to-severe ABI. It aimed also at investigating the possible relationship between the severity of disability and both psycho-emotional diseases and the presence of PTSD symptoms in patients with high metacognitive SA. Methods: Sixty patients with moderate-to-severe ABI and different levels of metacognitive SA completed a series of questionnaires, which assessed their self-reported metacognitive SA, anosodiaphoria, anxiety and depression, apathy, and PTSD symptoms. Results: Low-metacognitive-SA patients showed lower levels of anxiety and depression and higher anosodiaphoria than high-metacognitive-SA patients. Patients with high metacognitive SA and high levels of disability showed significant higher states of anxiety and PTSD symptoms than patients with high metacognitive SA and low levels of disability. Conclusions: The neurorehabilitation of individuals with moderate to severe ABI should address, in particular, the complex interaction between ISA and anxiety and depression in patients during the rehabilitation process.

Acquired Brain Injury (ABI) refers to brain damage resulting from traumatic or non-traumatic causes, including traumatic brain injury (TBI), stroke, anoxia, infection, or tumours (Kjeldgaard et al....