Spontaneous eye movements - (a) Conjugate deviation of the eyes suggests a focal hemispheric or brainstern lesion.

) Depression of eye movements may occur in mlotraln damage at level of Ihe tectum and occasionally In metabolic coma. (c) Shew deviation suggests a Jesior> at p onto medullary junction. fd) Dyscongugate eyes suggest damage to oculomotor or abducens nerve In brainstern or pathways. Repetitive conjugate horizontal ocular deviation ('ping-pong gaze1) is an incteaior of Orainstem lesions. Refractory nystagmus, in which the eyes jerk backwards in the orbits, usually indcates a mid-brain lesion. Intermittent jerking downward of the eyes [ocular boboing) Es seen with lesions in the low pons. 4. Reflex eye movements - (a) Oculo - cephalic response fcs tested by rotating Ihe patients head from side lo side and observing the position of the eyes. With intact brarnstem activity., Ihe eyes move congugatsly in a direction opposite to the head movements (doll's eye movements), but when the brainstem is depressed the eyes remain in the rhd-position ol the head. (b) Oculovestibular testing involves instilling 50-200 ml of ice cold water into the ear. Conscious patients, or those with psychogentc coma, will develop nystagmus with the quick phase away from the side ol the stimulation. A tonic response with conjugate movements of the eyes towards the stimulated side indicates an intact pons and suggests a supratentorial cause for the coma, a cVsconjugate response or absence of response, implies a lesion in the brainstern. 5. Respiratory pattern - Long-cycle Cheyne-Stokes respiration inofcaies damage at the levei of Ihe dlencephalon, and short-cysle occurs with damage at medullary level. Central neurogenlc hyperveniilaiion occurs with lesions in the tow rrid-braln and upper pons. Reflex responses such as yawning, vomiting and hiccough may occur with brainstern dsturbance. Acidotic respiration suggests diabetic Reioacitfosis or renal coma. 6. Motor function - is assessed for the Glasgow Corna Scale, but laleralizing abnormalities are important. (a) Generalized or focal seizures implies hemispheric damage and may help lataralizatlon. (b) Mulllfocal myoclonus favours a metabolic or anoxic cause for coma with effuse cortical irritation, (c) Tendon reflexes - Deep tendon reflexes and plantar response may also give clues to laleralizalion, implying a focal cause for coma, though focal signs may be seen in hepatic encephalopathy and hypoglycemia .7. INVOLUNTARY MOVEMENTS -