Sleep talking and primary progressive aphasia: case study and autopsy findings in a patient with logopenic primary progressive aphasia and dementia with Lewy bodies.

This case study highlights the parasomnia behaviours of an individual with primary progressive aphasia, a type of dementia known for decline in language abilities. Despite a paucity of speech during the day, this individual had concurrent sleep talking at night; a combination which, to our knowledge, has never been reported before. Post-mortem pathology confirmed clinical suspicion of both Alzheimer and Lewy body diseases, both asymmetric to the left side. Given this rare left-sided asymmetrical pathology, we hypothesise that the relatively preserved right hemisphere may have allowed for access to intact overlearned phrases which usually originate from the right hemisphere to appear while asleep. A second hypothesis is also presented which postulates that bottom-up processing may have overridden top-down apathy during sleep and allowed for speech output in this case. © BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.