Doll’s eye movements: presence of doll’s eye movements (occulocephalic reflex) in coma denotes that the brain stem is intact.
Cold caloric test: the fast component of nystagmus occurs towards the side which is being tested in an unconscious patient.
Conjugate lateral deviation of eyes: In cerebral lesion – towards the side of lesion.
In brain stem lesion: opposite to side of lesion.
Decerebrate rigidity: results from brain stem lesion anywhere between the inter-collicular level and vestibular nucleus and is characterized by extensor hypertonia and internal rotation of limbs with opisthotonus.
Decorticate rigidity: site of lesion is more cephalad at the interface of cerebral hemispheres and diencephalon. There is flexor hypertonia in upper limbs. No specificity regarding nature of lesion, these can occur transiently. Decerebrate rigidity has a grave prognosis.
These may be demonstrated in cases of:
Blunt head injury may present with hyperglycemia or renal glycosuria, subdural haematoma may present with signs of dehydration, intussusception may present as altered sensorium, in subclinical status epilepticus, patient is unresponsive, but the EEG shows discharges.
In assessing deterioration or improvement in the acute stage of coma as well as in predicting the ultimate outcome, the degree and duration of altered consciousness usually overshadow all other clinical features. It is therefore, vital to be able to assess and to record changing status of altered consciousness reliably.
The Glasgow Coma Scale is an effective method of describing the various states of impaired consciousness encountered in clinical practice. It is a practical system, can be used in a wide range of hospitals and by staff without special training. Three different aspects of behavioural responses examined are motor response, verbal response and eye opening, each being evaluated independently of the other. The responses are clearly defined and accurately graded according to a rank order that indicates the degree of dysfunction.
The Glasgow Coma Scale was earlier used only for head injury, but it is now used for all types of altered sensorium. The Glasgow Coma Scale has several limitations and in the following circumstances, its
Eye Opening Response (E)
Best verbal Response (V)
Best Motor Response (M)
Best score is E4 V5 M6 = 15
Worst score is E1 V1 M1 = 3
Interpretation may become erroneous: