Oculovestibular reflex (caloric stimulation) hepatic failure) may have exaggerated, brisk oculocephalic reflexes The eyes should gradually return to the mid-position in a smooth, conjugate movement if the brainstem is intact.These vertical responses indicates that the brainstem (CN3,4,8) is intact a similar result is seen when the head is flexed and extended - a positive result is downward deviation of the eyes during extension, and upward deviation during flexion (the eyelids, if closed, may also open as part of the ‘doll’s head phenomenon’).a positive response occurs when the eyes rotate to the opposite side to the direction of head rotation, thus indicating that the brainstem (CN3,6,8) is intact.the head is briskly turned from side to side with the head held briefly at the end of each turn.Oculocephalic reflex (‘doll’s eye’ reflex) This is suggestive of a pontine or vestibulocerebellar lesion on the side of the inferior eye, or a medial longitudinal fasciculus lesion on the side of the superior eyeĪbnormal eye position can also result from cranial nerve palsies (CN6 is particularly at risk due to it’s long course) and orbital entrapment in trauma.Vertical separation of the ocular axes is called skew deviation.Hence they can be distinguished clinically. Lateral gaze deviation from a pontine lesion cannot be overcome by stimulating oculocephalic or oculovestibular reflexes (see below), whereas supranuclear (e.g.A pontine lesion on the opposite side to the eye deviation. ‘Wrong way eyes’ may also be seen in thalamic hemorrhage.A frontal lobe lesion on the same side as the eye deviation, commonly a stroke. This can also be a result of a Todd’s paralysis following a seizure (whereas during the seizure the eyes deviate in the opposite direction - away from the origin of the ‘irritative’ focus).thus dysconjugate gaze is difficult to interpret in the stuporous or comatose patient.Most individuals have a degree of exophoria when drowsy for any reason and any underlying strabismus tends to worsen.ICH, PCOM aneurysm or raised ICP (parasympathetic nerves are in the superficial parts of the nerve, so tend to be more vulnerable to compressive lesions – ptosis and ‘down and out’ eye positioning tends not to occur due to sparing of the more central motor fibers) One dilated pupil suggests CN3 compression – e.g.fixed mid-sized pupils occur in midbrain lesions.pinpoint pupils occur in pontine lesions and certain overdoses (e.g.Different sized pupils correspond to different types of lesions.We need to assess the pupils for size, asymmetry and reactivity to light.Look for spontaneous breaths in the ventilated patient (may be suppressed if hyperventilated).Also look for deep rapid Kussmaul breathing, secondary to a metabolic acidosis, as in diabetes ketoacidosis.Central hyperventilation, or prolonged inspiratory pauses or irregular ataxic breathing indicates various brainstem lesions as does apnea.Cheyne-Stokes Respiration is not specific but is seen in lesions above the brainstem.Other scores such as the Richmond Agitation-Sedation Score (RASS) are used to titrate sedation (see Sedation in the ICU)īreathing pattern is often forgotten in intubated patients, but is important as the pattern of breathing correlates with the level of the lesion, and may suggest other causes.GCS is most commonly used (see Glasgow Coma Scale (GCS)).ventilator (evidence of spontaneous breaths?).cranial scars, drains, ICP monitors and VP shunts.consider the neurological findings in light of the vital signs, evidence of trauma, acute or chronic illness, and/or drug ingestion.Todd’s paresis, hemiparesis due to hypoglycemia) Remember that systemic causes can sometimes have focal signs! (e.g. Metabolic - check COATPEGS (CO2, O2, ammonia, temperature, pH, electrolytes, glucose, serum osmolality).Systemic causes without focal signs (TOMES) meningism - meningoencephalitis, subarachnoid haemorrhage (SAH).tumor, hemorrhage, abscess), injury, inflammation no meningism - stroke, space occupying lesions (e.g.In particular, assessment of asymmetry for the presence of focal neurological deficits is vital. meningism and signs of the underlying cause.motor responses (tone, reflexes and posturing).eye movements and oculovestibular responses.level of consciousness (Glasgow Coma Score - list the components e.g.The key components of the neurological examination of the comatose patient are: Coma is a state of unconsciousness caused by temporary or permanent impairment of the ascending reticular system in the brainstem, or both cerebral hemispheres.

Pinpoint pupil