Neurological examination

The neurological examination is the physical examination of the nervous system. It attempts to identify or exclude signs of nervous system disease, and - if these signs are present - to produce a likely anatomical or physiological explanation that can be tested through medical imaging, neurophysiology, blood tests, lumbar puncture or a combination.

The Neurological Examination is directed primarily towards the localization of lesions within the nervous system and is traditionally split into an examination of the cognitive state, cranial nerves, motor system, sensory system, cerebellar system, walking and gait and the extrapyramidal system.

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Central nervous system

• Assessment of consciousness, often using the Glasgow Coma Scale (EMV)
• Mental status examination, often including the abbreviated mental test score (AMTS) or mini mental state examination (MMSE)
• Global assessment of higher functions
• Intracranial pressure is roughly estimated by fundoscopy; this also enables assessment for microvascular disease

Peripheral nervous system

• Cranial nerves (I-XII): sense of smell (I), visual fields and acuity (II), eye movements (III, IV, VI) and pupils (III, sympathetic and parasympathetic), sensory function of face (V), strength of facial (VII) and shoulder girdle muscles (XI), hearing (VII, VIII), taste (VII, IX, X), pharyngeal movement and reflex (IX), tongue movements (XII)
• Reflexes: masseter, biceps and triceps tendon, knee tendon, ankle jerk and plantar (i.e. Babinski sign). Globally, brisk reflexes suggest an abnormality of the UMN or pyramidal tract, while decreased reflexes suggest abnormality in the anterior horn, LMN, peripheral nerve or motor end plate. A reflex hammer is used for this testing.
• Muscle strength (typically graded on the MRC scale I-V)
• Sensory system (to fine touch, pain, temperature)
• Muscle tone and signs of rigidity

Specific tests

• Finger-to-nose and ankle-over-tibia tests for ataxia
• Various tests for dysdiadochokinesis
• Tests for cogwheeling (abnormal tone suggestive of Parkinson's disease) or gegenhalten (more common in dementia). Gegenhalten is resistance to passive change, where the strength of antagonist muscles increases with increasing examiner force.
• Closer examination of any tremors
• Assessment of gait

Interpretation

The results of the examination are taken together to anatomically identify the lesion. This may be diffuse (e.g. neuromuscular diseases, encephalopathy) or highly specific (e.g. abnormal sensation in one dermatome due to compression of a specific spinal nerve by a tumor deposit). A differential diagnosis may then be constructed that takes into account the patient's background (e.g. previous cancer, autoimmune diathesis) and present findings to include the most likely causes. Examinations are aimed at ruling out the most clinically significant causes (even if relatively rare, e.g. brain tumor in a patient with subtle word finding abnormalities but no increased intracranial pressure) and ruling in the most likely causes.