Late Responses in the Electrodiagnosis of Cervical Radiculopathies.

BACKROUND AND AIM: This paper aims to assess the parameters of late responses and then determine their usefulness in patients with cervical radiculopathy.

PATIENTS AND METHODS: We studied a total of 114 patients with bilateral assessment of median and ulnar nerves and of F and A waves parameters.

RESULTS: We draw attention to the need of bilateral electrodiagnostic examination due to changes occurring in a third of cases also in the asymptomatic limb. Pluriradicular injuries occurred in one third of cases. The root that was most commonly affected in cases of uniradicular lesion was C7. The parameters with the most important alterations were persistence, tacheodispersion and chronodispersion, which were changed in about a half of the patients. With regard to the A wave, it occurred in a small number of cases, about 10%, with an average amplitude of about 120 μV and an average latency of 15ms. The distance from the point of stimulation where the collateral branch appeared was calculated to be approximately 35 cm.

CONCLUSIONS: Among the F wave parameters, persistence, tacheodispersion and chronodispersion are recommended to be studied; these parameters were also included in the composite score along with the AAEM recommendations.