Conduction velocity of the human phrenic nerve in the neck.
OBJECTIVE
To measure phrenic nerve conduction velocity in the neck in humans.


METHODS
We studied 15 healthy subjects (9 men, 32.4+/-6.7). We performed bipolar electrical phrenic stimulation in the neck, from a distal and a proximal stimulation site, and recorded diaphragm electromyographic responses on the surface of the chest. The ratio of the between-site distance to the latency difference provided phrenic velocities. Ulnar motor velocity was assessed similarly. In addition, five homogeneous patients with Charcot-Marie-Tooth disease type 1A (CMT1A) were studied for validation purposes. We obtained diaphragmatic responses from the two stimulation sites in all cases. The distal latencies (anterior axillary line recording) were 6.51+/-0.63ms (right) and 6.13+/-0.64ms (left). The minimal between site distance was 39mm. Phrenic motor velocity was 55.2+/-6.3ms(-1) (right) and 56.3+/-7.2ms(-1) (left). In CMT1A, phrenic velocities were 17.1+/-8.1ms(-1) (from 7 to 32ms(-1)) and were similar to ulnar and median velocities.


CONCLUSIONS
Phrenic nerve velocities can be estimated in humans and compare with upper limb motor conduction velocities. This should refine the investigation of phrenic function in peripheral neuropathies.
Morélot-Panzini
Capucine
C
Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Laboratoire de Physiopathologie Respiratoire du Service de Pneumologie et Réanimation, Paris, France.
Fournier
Emmanuel
E
Donzel-Raynaud
Christine
C
Dubourg
Odile
O
Willer
Jean-Claude
JC
Similowski
Thomas
T
D000328:Adult; D002607:Charcot-Marie-Tooth Disease / Q000503:physiopathology; D003964:Diaphragm / Q000294:innervation; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology / Q000503:physiopathology; D008875:Middle Aged; D009333:Neck; D009431:Neural Conduction / Q000502:physiology*; D010791:Phrenic Nerve / Q000502:physiology* / Q000503:physiopathology; D011930:Reaction Time; D014459:Ulnar Nerve / Q000502:physiology / Q000503:physiopathology