REM sleep components predict the response to initial treatment of infantile spasms.
OBJECTIVE
The phasic inhibition index (PII) is the rate of the simultaneous occurrence of rapid eye movement bursts (RBs) and phasic chin muscle activity (PCMA) during rapid eye movement sleep (REMS). PII is low insofar as physiologically occurring REM-related phasic inhibition acts on chin muscles. Previously we found that PII was significantly higher in patients with infantile spasms (ISs) who had a recurrence of convulsions than in patients with ISs who exhibited no recurrence. We aimed to predict the response of patients with ISs to conventional anticonvulsants (AEDs) by means of REMS components including PII, expecting to facilitate avoidance of potentially hazardous hormonal therapy.


METHODS
REMS, recorded before the beginning of any medication, was retrospectively examined in 15 patients with ISs. The patients were classified into two groups according to the response to initial treatment with conventional AEDs. Conventional AEDs were enough to control the spasms in six good responders (GRs), whereas further hormonal therapy was required in nine poor responders (PRs) to control the spasms.


RESULTS
The amount of REMS was significantly lower in patients with ISs than in controls. GRs had less REMS than did PRs, although no significant difference was observed. Although the frequencies of RB and PCMA showed no significant differences among GRs, PRs, and controls, the average PII value in PRs (12.6+/-3.4; mean+/-SD) was significantly (p < 0.001) higher than that in GRs (6.1+/-1.7).


CONCLUSIONS
PII is a useful parameter for differentiating GRs from PRs.
Department of Pediatrics, Faculty of Medicine, Tokyo Medical and Dental University, Yushima, Japan.
J
J
Kohyama
J
J
Sugimoto
M
M
Itoh
H
H
Sakuma
M
M
Shimohira
T
T
Hasegawa
Y
Y
Iwakawa
D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use*; D002680:Chin / Q000502:physiology; D004576:Electromyography; D006801:Humans; D007231:Infant, Newborn; D009119:Muscle Contraction / Q000502:physiology; D009132:Muscles / Q000502:physiology; D017286:Polysomnography; D012189:Retrospective Studies; D012895:Sleep, REM / Q000502:physiology*; D013036:Spasms, Infantile / Q000175:diagnosis* / Q000188:drug therapy* / Q000503:physiopathology; D016896:Treatment Outcome
D000927:Anticonvulsants