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Flexor carpi radialis H-reflex modulation during spinal loading and unloading with varied forearm postures.
Hesham N Alrowayeh1, Mohamed A Sabbahi, Bruce Etnyre
1Physical Therapy Department, Faculty of Allied Health Sciences, Kuwait University, Sulaibekhat, State of Kuwait. hrowayeh@hsc.edu.kw
Summary
The flexor carpi radialis (FCR) H-reflex is larger when the forearm is pronated and during sitting postures compared to lying. These findings suggest optimal conditions for FCR H-reflex recordings.
Area of Science:
- Neurophysiology
- Clinical Electrophysiology
Background:
- The flexor carpi radialis (FCR) H-reflex is used to detect C7 radiculopathy.
- Previous studies have not investigated FCR H-reflex during postural loading or compared forearm supination and pronation effects.
Purpose of the Study:
- To examine FCR H-reflex amplitude under varied cervical spine loadings and forearm positions.
- To determine optimal conditions for FCR H-reflex recording.
Main Methods:
- Recorded maximum FCR H-reflex amplitude in 15 healthy participants.
- Tested conditions: lying, free-sitting, sitting-with-load, with forearm in supination or pronation.
- Utilized two-way repeated-measure ANOVA for statistical analysis.
Main Results:
- FCR H-reflex amplitude was significantly greater in free-sitting and sitting-with-load compared to lying.
- FCR H-reflex amplitude was significantly greater in forearm pronation versus supination.
- Augmentation observed in pronation and sitting postures suggests neural and mechanical influences.
Conclusions:
- Sitting postures and forearm pronation enhance FCR H-reflex amplitude.
- Recommends performing FCR H-reflex recordings in a sitting position with the forearm pronated.
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