A significant correlation between cauda equina conduction time and cerebrospinal fluid protein in chronic inflammatory demyelinating polyradiculoneuropathy.

We investigated the relationship between the involvement of the cauda equina in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and the increment of cerebrospinal fluid (CSF) protein. We measured cauda equina conduction time (CECT) in 14 CIDP patients using magnetic stimulation with a MATS coil. Statistical analysis revealed that CECT and CSF protein had a significant positive linear correlation. Conduction time of the peripheral nerve trunk, in contrast, had no significant linear correlation with CSF protein. We revealed that the involvement of the cauda equina and increment of CSF protein are closely related. In CIDP cases with elevated CSF protein, spinal nerves including the cauda equina are very likely involved.