Clinical and electromyographic deep tendon reflexes in polyneuropathy: diagnostic value and prevalence*.
BACKGROUND
Evidence is accumulating that patients with polyneuropathy may present with normal clinical deep tendon reflexes (C-DTR). There are few studies that assessed the diagnostic utility of electromyographically recorded DTR (Er-DTR) in patients with polyneuropathy.


OBJECTIVE
The objectives of this study were twofold: (i) to evaluate the prevalence of preserved C-DTR in polyneuropathy; (ii) diagnostic value of Er-DTR latency measurement in patients with polyneuropathy.


METHODS
We prospectively studied 38 controls and 185 patients with polyneuropathy. All subjects had evaluation of C-DTR, Er-DTR obtained from right biceps brachii (BR), right patellar (PR) and bilateral ankle reflexes (AR).


RESULTS
Of these 185 patients, 118 (63.8%) had chronic axonal neuropathy (CAN), 49 (26.5%) demyelinating polyradiculoneuropathy (DPN) and 18 (9.7%) small fiber neuropathy (SFN). The C-DTR were normal in 65 patients whereas 39 of these 65 (60%) patients had abnormalities of Er-DTR at one or more sites. Er-DTR latencies in patients with polyneuropathies were prolonged at all sites compared with controls (P < 0.01). Among patients with various types of polyneuropathies the Er-DTR, mean latencies at all the sites and latency indicative of demyelination (>150% of the normal mean) were higher in patients with DPN than that of CAN or SFN (P < 0.01).


CONCLUSIONS
We conclude that C-DTR are preserved in 35.1% of the patients with polyneuropathies and Er-DTR should be performed in such patients in order to provide electrophysiological evidence of a polyneuropathy. Er-DTR are useful in distinguishing axonal from demyelinating disorders of peripheral nerve, and detection of subclinical involvement of large fibers in SFN.
Sharma
K R
KR
Department of Neurology, University of Miami School of Medicine, FL 33136, USA. ksharma@med.miami.edu
Saadia
D
D
Facca
A G
AG
Resnick
S
S
Ayyar
D R
DR
D001132:Arm / Q000503:physiopathology; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology; D006801:Humans; D007866:Leg / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D011115:Polyneuropathies / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D012018:Reflex / Q000502:physiology*; D013710:Tendons / Q000503:physiopathology