Reduced sleep efficiency in cervical spinal cord injury; association with abolished night time melatonin secretion.
METHODS
Case-controlled preliminary observational study.


OBJECTIVE
Melatonin is usually secreted only at night and may influence sleep. We previously found that complete cervical spinal cord injury (SCI) interrupts the neural pathway required for melatonin secretion. Thus, we investigated whether the absence of night time melatonin in cervical SCI leads to sleep disturbances.


METHODS
General Clinical Research Center, Brigham and Women's Hospital, Boston, USA.


METHODS
In an ancillary analysis of data collected in a prior study, we assessed the sleep patterns of three subjects with cervical SCI plus absence of nocturnal melatonin (SCI levels: C4A, C6A, C6/7A) and two control patients with thoracic SCI plus normal melatonin rhythms (SCI levels: T4A, T5A). We also compared those results to the sleep patterns of 10 healthy control subjects.


RESULTS
The subjects with cervical SCI had significantly lower sleep efficiency (median 83%) than the control subjects with thoracic SCI (93%). The sleep efficiency of subjects with thoracic SCI was not different from that of healthy control subjects (94%). There was no difference in the proportion of the different sleep stages, although there was a significantly increased REM-onset latency in subjects with cervical SCI (220 min) as compared to subjects with thoracic SCI (34 min). The diminished sleep in cervical SCI was not associated with sleep apnea or medication use.


CONCLUSIONS
We found that cervical SCI is associated with decreased sleep quality. A larger study is required to confirm these findings. If confirmed, the absence of night time melatonin in cervical SCI may help explain their sleep disturbances, raising the possibility that melatonin replacement therapy could help normalize sleep in this group.
Scheer
F A J L
FA
Harvard Medical School and Division of Sleep Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
Zeitzer
J M
JM
Ayas
N T
NT
Brown
R
R
Czeisler
C A
CA
Shea
S A
SA
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000293:injuries / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D010865:Pilot Projects; D012189:Retrospective Studies; D020178:Sleep Disorders, Circadian Rhythm / Q000097:blood* / Q000209:etiology; D013119:Spinal Cord Injuries / Q000097:blood* / Q000150:complications; D013223:Statistics as Topic
D008550:Melatonin