Paroxysmal attacks are short, frequent and stereotyped symptoms that can be observed in various clinical conditions. They are usually associated with Multiple Sclerosis, but they may also be observed in other disorders such as encephalitis, head trauma, stroke and Behcet's disease.

Paroxysmal attacks in various disorders have been reported extensively and ephaptic transmission of demyelinated nerves has been presumed as one of the underlying mechanisms of this phenomenon. Exercise, tactile stimuli, hot water, anxiety and neck flexion may provoke paroxysmal attacks. Mostly reported paroxysmal attacks are painful tonic spasms, dysarthria and ataxia, numbness and hemiparesis. They are typically different from other transient symptoms by their brevity (lasting no more than 2 minutes), frequency (from 1-2 times/day up to a few hundred times/day), stereotyped fashion and excellent response to drugs (usually carbamazepine). Withdrawal of symptoms without any residual neurological finding is another key feature in their recognition.