Clinical neurophysiology in Trinidad and Tobago - abstract

ABSTRACT

The clinical neurophysiological techniques available in Trinidad and Tobago are electroencephalography (EEG) nerve conduction studies (NCS) and electromyography (EMG). Two hundred consecutive EEGs and 100 consecutive NCS and 27 EMGs were retrospectively evaluated to determine the usefulness of these studies. EMGs were done on a Grass model 8/10 D, 8 channel recorder. The commonest symptoms investigated were seizures (78), headaches (42), post concussion syndrome (41), cerebral contusion (19), blackouts (17), dizziness (7) and stroke syndrome (7). Seizure were confirmed in 2718, generalised; 7, focal, and 2, focal spreading to generalised. One showed the petit mal pattern of 3 per second spike and wave and another hypsarrhythmia. Eight out of 16 with febrile convulsions had paroxysmal activity. Of patients with headaches, 8 were abnormal, showinf focal slowing (6) and diffuse slowing (2). All patients with blackouts had normal tracings. Slow activity eas seen in 2 cases of dizziness and in 5 of stroke syndrome. In post concussion, 5 showed slowing and 1 sharp activity. NCS and EMG were done on a TECA model B6 machine. NCS were most commonly done on median nerve (75), ulnar (48), radial (15), and peroneal (20). EMG most frequently tested the biceps and deltoid. NCS confirmed compression of the median nerve (carpal tunnel syndrome) in 23, ulnar in 1, peroneal in 2 and medial plantar (tarsal tunnel syndrome) in 1. NCS also confirmed injury in the median nerve (6), ulnar (1), radial (4), multiple upper extremity nerves (2), brachial plexus 1, sciatic (1) and peroneal (1). Four cases of peripheral neuropathy indicated Guillan-Barre in 2 and motor neurone disease was suggested in another 4. EMG confirmed nerve injury and various stages of recovery in 9, motor neurone disease in 5 and myasthenia gravis in 1. EEG was useful in selecting patients for further studies. NCS identified specific nerve compression or injury and further evaluated cases of generalised neuropathy. EMG served to clarify and determine prognosis in nerve injury and compression and was valuable in the evaluation of generalised nerve and primary muscle disease (AU)