Diagnostic utility of F waves in cervical radiculopathy: electrophysiological and magnetic resonance imaging correlation.
OBJECTIVE
F wave study is a simple, non-invasive method commonly utilized for evaluation of cervical root lesions. Its diagnostic sensitivity is low. There are no large series comparing F wave studies with MRI as a reference standard.


METHODS
We performed F wave studies in 30 controls (15 men; mean age: 50 years; standard deviation: 17.9 years; range: 21-80 years) and, prospectively, 31 patients (19 men; mean age: 48 years; standard deviation: 16.2 years; range: 26-79 years) referred for evaluation of cervical spondylotic radiculopathy (CSR). All patients' MRIs were compared with F wave parameters.


RESULTS
Combined utilization of minimal F latency, F chronodispersion, F persistence and side to side differences resulted in 55% sensitivity and 100% side concordance for detecting CSR, with MRI as a comparison standard. F wave parameters also provided complementary information to needle electromyography in the diagnostic evaluation of CSR. Although F waves were not indicative of radiculopathy levels, 4/31 (13%) of cases had at least one abnormal F wave parameter, despite normal electromyography findings.


CONCLUSIONS
Combined utilization of multiple F wave parameters is a useful, diagnostic adjunct in the electrophysiological evaluation of CSR.
Lo
Y L
YL
Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Outram Road, Singapore 169608, Singapore. gnrlyl@sgh.com.sg
Chan
L L
LL
Leoh
Th
T
Lim
W
W
Tan
S B
SB
Tan
C T
CT
Fook-Chong
S
S
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae; D004576:Electromyography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011843:Radiculopathy / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D013128:Spinal Osteophytosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology*