To determine values of F-wave parameters for the tibial nerve in clinically normal Miniature Dachshunds and those with thoracolumbar intervertebral disk herniation (IVDH).
53 Miniature Dachshunds (10 clinically normal and 43 with various clinical grades of thoracolumbar IVDH).
F-waves were elicited in the interosseous muscles of 1 hind limb in each dog by stimulation of the tibial nerve. F-wave parameters were measured for 32 stimuli/dog, and mean values were calculated. Linear regression was performed to assess correlations between F-wave parameters and clinical severity of IVDH.
For clinically normal dogs, mean ± SD values of shortest F-wave latency, mean F-wave conduction velocity, mean F-wave duration, and ratio of the mean F-wave amplitude to M response amplitude were 8.6 ± 0.6 milliseconds, 83.7 ± 6.1 m/s, 6.6 ± 1.5 milliseconds, and 9.8 ± 8.5%, respectively. F-wave persistence was 100%. Mean F-wave duration was positively correlated with clinical grade of IVDH. Linear regression yielded the following regression equation: F-wave duration (milliseconds) = 6.0 + 2.7 × IVDH grade. One dog with grade 2 IVDH had a mean F-wave duration shorter than that of all 5 dogs with grade 1 IVDH; 1 dog with grade 3 IVDH had a longer duration than that of all 10 dogs with grade 4 IVDH.
CONCLUSIONS AND CLINICAL RELEVANCE
Mean F-wave duration was correlated with the severity of inhibitory motor tract dysfunction in the spinal cord of dogs. F-wave examination may be useful for objective functional evaluation of upper motor neurons in the spinal cord.
Objective—To establish a method of F-wave examinations
and to determine values of F-wave conduction
velocity (FWCV) and F-wave latency for the tibial
nerve of clinically normal dogs.
Animals—21 clinically normal dogs.
Procedure—The F-waves were elicited from the
interosseous muscles via stimulation of the tibial
nerve. The FWCV was determined by using the F-wave
shortest value and the surface distance corresponding
to the tibial nerve length. Correlation
between the smallest latency value of the F-wave and
the length of the tibial nerve and between the FWCV
and rectal temperature were closely examined.
Results—F-wave latency was proportional to the
length of the tibial nerve (correlation coefficient,
0.929). Mean ± SD FWCV was 77.98 ± 8.62 m/s.
Regression equation was as follows: F-wave latency =
2.799 + (0.029 X length of the tibial nerve). The FWCV
was increased when the measured rectal temperature
was high. Correlation coefficient between FWCV
and rectal temperature was 0.665.
Conclusion and Clinical Relevance—In the study
reported here, we established a reliable method for
clinical evaluation of the F-wave. When assessing
nerve conduction velocity, it is essential to measure
nerve length along the pathway that the nerve
impulse travels. This method of F-wave examination is
a useful diagnostic tool for the evaluation of suspected
dysfunction of the peripheral nervous system.
(Am J Vet Res 2002;63:1262–1264)
Objective—To establish a method of F-wave evaluation and to determine normative values of F-wave parameters, including F-wave conduction velocity, persistence, and amplitude for the tibial nerve in cats.
Animals—30 clinically normal cats.
Procedures—F-waves elicited in the interosseous muscles by stimulation of the tibial nerve were recorded, and linear regression analyses of the shortest latency versus the length of the tibial nerve and the limb length were performed. F-wave persistence was calculated by dividing the number of recorded F-waves by the number of stimuli.
Results—The correlation coefficient between F-wave latency and nerve length was 0.92, and that between F-wave latency and limb length was 0.58. Mean ± SD F-wave conduction velocity of the tibial nerve was calculated to be 97.1 ± 5.0 m/s. Linear regression analysis yielded the regression equation as follows: F-wave latency (milliseconds) = 2.60 + (0.02 × nerve length [mm]). Mean F-wave persistence and amplitude were 98.7 ± 2.3% and 1.01 ± 0.62 mV, respectively.
Conclusions and Clinical Relevance—Results indicated that nerve length should be used for nerve conduction studies of F-waves in felids. The regression equation for F-wave latency, conduction velocity, persistence, and amplitude may contribute to the diagnosis of nervous system diseases or injury in cats, such as trauma to the spinal cord or diabetic neuropathy.