Self-Injurious Behavior in a Patient With Dementia: A Case Report and Literature Review.

Self-injurious behavior (SIB) has frequently been associated with psychiatric illness and neurological lesions as means of reducing tension or diverting from pain. However, these explanations did not capture the complexity of SIB in the case of Mr. X, a 62-year-old patient who ingested his fingers in his sleep where cognitive testing was valuable in informing diagnosis. Mr. X's SIB was severe enough that he had chewed beyond the middle phalanx for most of his fingers. Clinical symptoms included daytime sleepiness, hypnogogic hallucinations, and bradykinesia. His cognitive profile revealed declines in his intellectual functioning as well as visuospatial and executive deficits in the context of preserved attention, language, and memory. His cognitive and clinical presentation suggested that Mr. X had a neurodegenerative disorder, which may have contributed to his SIB. We believed that the most probable diagnosis may have been rapid eye movement behavioral sleep disorder in the context of Lewy bodies dementia.