Repeatability of electromyography and force measurements of the neck muscles in adolescents with and without headache.
BACKGROUND
Reliable measurements are needed to study the dysfunction of the neck muscles. The aim of this study was to determine the intra-tester repeatability of EMG and isometric force measurements of the neck muscles in adolescents with headache and headache-free controls.


METHODS
A group of 30 adolescents with migraine-type headache, 29 with tension-type headache, and 30 headache-free controls were recruited. Maximal isometric neck muscle force with simultaneous recording of surface EMG from the cervical erector spinae and the sternocleidomastoideus muscles was measured twice during one day.


RESULTS
For all groups, intra-class correlation coefficients (ICC) and coefficients of variation (CV) showed acceptable repeatability of all measurements. (Force measurements: ICC 0.98-0.99, CV 0.7-3.7%; EMG measurements: ICC 0.95-0.99, CV 4.9-10.1%.) On the individual level, variation between the consecutive measurements was found to be low in all groups.


CONCLUSIONS
The present EMG and force measurements of neck muscles indicate acceptable intra-tester repeatability in adolescents. The repeatability was comparable in migraine- and tension-type headache and headache-free groups. The EMG and the force measurements offer the possibility to investigate neck muscle dysfunction in adolescent headache.
Oksanen
Airi
A
Department of Physical and Rehabilitation Medicine, Turku University Central Hospital, P.O. Box 52, FIN-20521 Turku, Finland. airi.oksanen@tyks.fi
Ylinen
Jari J
JJ
Pöyhönen
Tapani
T
Anttila
Pirjo
P
Laimi
Katri
K
Hiekkanen
Heikki
H
Salminen
Jouko J
JJ
D000293:Adolescent; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008881:Migraine Disorders / Q000503:physiopathology*; D053581:Muscle Strength Dynamometer; D009334:Neck Muscles / Q000502:physiology*; D015203:Reproducibility of Results; D012399:Rotation; D018781:Tension-Type Headache / Q000503:physiopathology*