A variety of electrodiagnostic methods are used to confirm the diagnosis of a cute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are freq uent during the first few weeks of weakness. We compared t...A variety of electrodiagnostic methods are used to confirm the diagnosis of a cute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are freq uent during the first few weeks of weakness. We compared the nerve conduction st udies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with gra ded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definit e) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95 - 100% , P < .0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute de myelination (sensitivity 48% , specificity 96% , P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory r esponse amplitudes were lower in the CIP group, with comparable mean motor and s ensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The fr equency of absent or delayedFwaves and absent H reflex was similar in both group s. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r=0.9). We conclude tha t a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.展开更多
Motor involvement in common peroneal neuropathy (CPN)-frequently shows a sele ctive pattern with regard to deep and superficial divisions of the peroneal nerv e, by clinical examination and needle electromyography. Th...Motor involvement in common peroneal neuropathy (CPN)-frequently shows a sele ctive pattern with regard to deep and superficial divisions of the peroneal nerv e, by clinical examination and needle electromyography. The involvement of the s ensory branch of the superficial peroneal nerve (SPN) has not been well establis hed using nerve conduction studies. Among 42 cases of electrophysiologically def ined CPN in 35 patients, 37 (88%) had clinical or electrophysiologic evidence f or SPN involvement, but only 20 had diminished superficial peroneal sensory resp onse (SPSR) amplitudes. Many of the cases involving normal SPSRs had significant axonal loss involving deep peroneal motor fibers. Sparing of the superficial pe roneal sensory fibers provides further evidence for the selective vulnerability of different nerve fascicles to injury. This is an important pattern to recogniz e; from a practical standpoint, focal segmental conduction abnormalities in the motor nerve and EMG findings can help to differentiate these lesions from L-5 r adiculopathy.展开更多
文摘A variety of electrodiagnostic methods are used to confirm the diagnosis of a cute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are freq uent during the first few weeks of weakness. We compared the nerve conduction st udies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with gra ded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definit e) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95 - 100% , P < .0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute de myelination (sensitivity 48% , specificity 96% , P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory r esponse amplitudes were lower in the CIP group, with comparable mean motor and s ensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The fr equency of absent or delayedFwaves and absent H reflex was similar in both group s. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r=0.9). We conclude tha t a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.
文摘Motor involvement in common peroneal neuropathy (CPN)-frequently shows a sele ctive pattern with regard to deep and superficial divisions of the peroneal nerv e, by clinical examination and needle electromyography. The involvement of the s ensory branch of the superficial peroneal nerve (SPN) has not been well establis hed using nerve conduction studies. Among 42 cases of electrophysiologically def ined CPN in 35 patients, 37 (88%) had clinical or electrophysiologic evidence f or SPN involvement, but only 20 had diminished superficial peroneal sensory resp onse (SPSR) amplitudes. Many of the cases involving normal SPSRs had significant axonal loss involving deep peroneal motor fibers. Sparing of the superficial pe roneal sensory fibers provides further evidence for the selective vulnerability of different nerve fascicles to injury. This is an important pattern to recogniz e; from a practical standpoint, focal segmental conduction abnormalities in the motor nerve and EMG findings can help to differentiate these lesions from L-5 r adiculopathy.
