SSEP and F-wave studies in acute inflammatory demyelinating polyradiculoneuropathy

Somatosensory evoked potentials (SSEPs) and F‐wave responses were compared after tibial (PTN) and median (MN) nerve stimulation in patients with acute inflammatory demyelinating polyradiculoneuropathy (AIDP). Nineteen patients were evaluated within 2 weeks of AIDP onset. Each had F‐wave and PTN‐SSEP studies; 18 had MN‐SSEP studies. Ten patients had absent or prolonged MN‐SSEP latencies, whereas 16 had abnormal MN F‐wave studies. Seventeen patients had an abnormal PTN‐SSEP while 12 had abnormal PTN F waves. Every patient with an abnormal MN‐SSEP also had an abnormal PTN‐SSEP. The most common PTN‐SSEP findings were an absent or prolonged latency of N8 or N22. All patients had either an abnormal MN F wave or PTN‐SSEP.