Electromyography in Patients on Chronic Pyridostigmine Therapy

Electromyography With Repetitive Nerve Stimulation in Patients on Chronic Pyridostigmine Therapy

We intend to measure evoked EMG at two sites in subjects who are chronically taking pyridostigmine.

The investigators are intending to enroll Patients who are chronically treated with pyridostigmine for the treatment of any medical condition and presenting at the investigators' outpatient clinics for follow up appointment. Subjects taking pyridostigmine for the treatment of myasthenia gravis will be excluded. Both adults and children older than 12 years of age will be approached. Those subjects that agree to participate will be asked to sign an informed consent. For the participation of minors a parental (or guardian) consent and subject assent will be obtained. Those that participate will answer a few questions pertaining to their medical history and will then undergo electromyograph (CMAP) measurement with repetitive stimulation at 2 sites (ulnar nerve at the wrist and the accessory nerve in the neck). Evoked electromyogram will be recorded on a computer hard drive. Eight percent or greater decrement in the CMAP response on repetitive stimulation will be considered positive.

Inclusion Criteria:

• Subjects who have been taking pyridostigmine for the treatment of any condition other than myasthenia gravis

Exclusion Criteria

• Subjects taking pyridostigmine for the treatment of myasthenia gravis will be excluded.