Insights into REM sleep behavior disorder pathophysiology in brainstem-predominant Lewy body disease.
OBJECTIVE
Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia reflecting changes in the brain, but which specific neuronal networks are involved in human RBD pathogenesis has not yet been determined. To date, only one case of idiopathic RBD has undergone autopsy, in which "incidental Lewy body disease" was found. Due to the severe neuronal loss and gliosis in the substantia nigra (SN) and locus ceruleus (LC) in this case, degeneration of brainstem monoaminergic neurons was postulated as the underlying substrate for RBD. Additional cases of idiopathic RBD with neuropathologic examination may help clarify which key brainstem structures are involved.


METHODS
Case report with neuropathologic analysis.


RESULTS
A man with polysomnographically proven RBD (onset age 57 years), but no other neurologic signs or symptoms, underwent neuropathologic examination upon his death at age 72. Histopathologic analysis showed Lewy body disease, but no significant neuronal loss or gliosis was present in the SN or LC.


CONCLUSIONS
This case represents another example of Lewy body disease associated with RBD. The minimal degenerative changes in the SN and LC call into question the role of these nuclei in RBD, at least in our case. We suggest additional cases of idiopathic RBD undergo neuropathologic analyses to better delineate the neurologic substrate of this intriguing parasomnia.
Boeve
B F
BF
Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA. bboeve@mayo.edu
Dickson
D W
DW
Olson
E J
EJ
Shepard
J W
JW
Silber
M H
MH
Ferman
T J
TJ
Ahlskog
J E
JE
Benarroch
E E
EE
D000368:Aged; D001933:Brain Stem / Q000503:physiopathology*; D004417:Dyspnea / Q000175:diagnosis / Q000503:physiopathology*; D004576:Electromyography; D005911:Gliosis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020961:Lewy Body Disease / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D016874:Neurofibrillary Tangles / Q000378:metabolism / Q000473:pathology; D017286:Polysomnography; D012720:Severity of Illness Index; D012895:Sleep, REM / Q000502:physiology*; D051844:alpha-Synuclein / Q000378:metabolism
D051844:alpha-Synuclein