Thenar muscles H reflex in patients with fibromyalgia: A case control study.
OBJECTIVE
To delineate H-reflex parameters and specify the diagnostic accuracy measures of thenar muscle H-reflex in Fibromyalgia (FM).


METHODS
The study was a cross sectional study performed on 30 subjects with FM and 30 healthy volunteers in two major referral hospitals. We recorded the number of obtainable thenar H-reflexes and their minimum latency, threshold and amplitude in each group.


RESULTS
There was a significantly more chance to elicit the H-reflex in patients with FM. H reflex threshold and minimum latency were lower in FM group but no significant difference was shown for H wave amplitude. According to our study, thenar H-reflex has 46.7% sensitivity, 86.7% specificity and 66.7% diagnostic accuracy to detect FM. It also has moderate predictive values and positive likelihood ratio but low negative likelihood ratio.


CONCLUSIONS
Higher rate of thenar muscle H-reflex in fibromyalgia can be interpreted as a confirmatory finding to central sensitization theory for this disorder. Obtaining H-reflex from thenar muscles could be a helpful diagnostic tool for fibromyalgia that increases the confidence in diagnosis. Although it is a weak tool for screening because of low sensitivity, it has a relatively high specificity.
K
K
Azma
S A
SA
Raeissadat
A
A
Hosseini
H
H
Mahmoudi
M
M
Sepehrian
Z
Z
Salehi
D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology*; D006181:H-Reflex; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015203:Reproducibility of Results; D013933:Thumb / Q000503:physiopathology*