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In patients with chronic pain it is essential to perform a comprehensive neurological examination in addition to a routine physical assessment. The neurological examination should evaluate2:
- Mental status
- Motor system
- Sensory perception
- Deep tendon reflex
- Cranial nerve function
(i) Mental status
An evaluation of mental status should assess the patient’s level of alertness; degree of orientation with respect to time, place and person; general appearance; behaviour and mood; and intellectual function including comprehension, ability to pay attention, insight and memory. The patient may be asked to remember several objects mentioned earlier in the course of the examination, to repeat sentences, to solve simple mathematical problems or to carry out commands of graded complexity2.
(ii) Motor system
An evaluation of motor system should check the appearance of the muscles (e.g. atrophy), their tone, (e.g. flaccid) and strength. Observation of gait can provide information on muscle strength; any indication of impaired vestibular, cerebellar or dorsal column function should be documented. Latent weakness can be detected by asking patients to walk on their toes and heels. Heel walking is the most sensitive bedside test for weakness of foot dorsiflexion, while toe walking is the best way to detect early weakness of foot plantar flexion2.
Muscle atrophy can be documented by circumferential measurements of the extremities (e.g. the calf and thigh bilaterally). A difference of 2 cm or more at the same level is indicative of atrophy2.
(iii) Sensory perception
Sensory perception can be evaluated with different types of stimuli, such as light touch, painful squeeze or pinprick, temperature and pressure/vibration. A freshly opened alcohol wipe may be used as a bedside probe of deficits in cold perception, or to elicit cold allodynia (pain produced by a non-noxious stimulus)2.
(iv) Deep tendon reflex
This is the most objective part of the neurological examination, since the reflexes are not under voluntary control and testing does not depend on the patient’s cooperation. Alterations in reflexes are often early signs of neurological dysfunction2.
(v) Cranial nerve function.
The 12 cranial nerves relay messages between the brain and the head and neck. They mediate motor and sensory functions, including vision, smell, and movement of the tongue and vocal cords. The evaluation of the fifth cranial nerve (affected in trigeminal neuralgia) requires the assessment of facial sensation, jaw strength and movement, and corneal reflexes2.
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