Neurological examination


A neurological examination is the assessment of sensory neuron and motor responses, especially reflexes, to determine whether the nervous system is impaired. This typically includes a physical examination and a review of the patient's medical history, but not deeper investigation such as neuroimaging. It can be used both as a screening tool and as an investigative tool, the former of which when examining the patient when there is no expected neurological deficit and the latter of which when examining a patient where you do expect to find abnormalities. If a problem is found either in an investigative or screening process, then further tests can be carried out to focus on a particular aspect of the nervous system.
In general, a neurological examination is focused on finding out whether there are lesions in the central and peripheral nervous systems or there is another diffuse process that is troubling the patient. Once the patient has been thoroughly tested, it is then the role of the physician to determine whether these findings combine to form a recognizable medical syndrome or neurological disorder such as Parkinson's disease or motor neurone disease. Finally, it is the role of the physician to find the cause for why such a problem has occurred, for example finding whether the problem is due to inflammation or is congenital.

Indications

A neurological examination is indicated whenever a physician suspects that a patient may have a neurological disorder. Any new symptom of any neurological order may be an indication for performing a neurological examination.

Patient's history

A patient's history is the most important part of a neurological examination and must be performed before any other procedures unless impossible. Important factors to be taken in the medical history include:
Handedness is important in establishing the area of the brain important for language. As patients answer questions, it is important to gain an idea of the complaint thoroughly and understand its time course. Understanding the patient's neurological state at the time of questioning is important, and an idea of how competent the patient is with various tasks and his/her level of impairment in carrying out these tasks should be obtained. The interval of a complaint is important as it can help aid the diagnosis. For example, vascular disorders occur very frequently over minutes or hours, whereas chronic disorders occur over a matter of years.
Carrying out a 'general' examination is just as important as the neurological exam, as it may lead to clues to the cause of the complaint. This is shown by cases of cerebral metastases where the initial complaint was of a mass in the breast.

List of tests

Specific tests in a neurological examination include the following:
CategoryTestsExample
Mental status examination
"A&O x 3, short and long-term memory intact"
Cranial nerve examinationCranial nerves : sense of smell, visual fields and acuity, eye movements and pupils, sensory function of face, strength of facial and shoulder girdle muscles, hearing, taste, pharyngeal movement and reflex, tongue movements. These are tested by their individual purposes."CNII-XII grossly intact"
Motor system
  • Muscle strength, often graded on the MRC scale 0 to 5.
  • * grades 4−, 4 and 4+ maybe used to indicate movement against slight, moderate and strong resistance respectively.
  • Muscle tone and signs of rigidity.
  • Examination of posture
  • * Decerebrate
  • * Decorticate
  • * Hemiparetic
  • Resting tremors
  • Abnormal movements
  • * Seizure
  • * Fasciculations
  • * Tone
  • ** Spasticity
  • *** Pronator drift
  • ** Rigidity
  • *** Cogwheeling
  • *** Gegenhalten – is resistance to passive change, where the strength of antagonist muscles increases with increasing examiner force. More common in dementia.
  • "strength 5/5 throughout, tone WNL"
    Deep tendon reflexesReflexes: masseter, biceps and triceps tendon, knee tendon, ankle jerk and plantar. Globally, brisk reflexes suggest an abnormality of the UMN or pyramidal tract, while decreased reflexes suggest abnormality in the anterior horn, LMN, nerve or motor end plate. A reflex hammer is used for this testing."2+ symmetric, downgoing plantar reflex"
    SensationSensory system testing involves provoking sensations of fine touch, pain and temperature. Fine touch can be evaluated with a monofilament test, touching various dermatomes with a nylon monofilament to detect any subjective absence of touch perception.
    "intact to sharp and dull throughout"
    Cerebellum
  • Cerebellar testing
  • * Dysmetria
  • ** Finger-to-nose test
  • ** Ankle-over-tibia test
  • * Dysdiadochokinesis
  • ** Rapid pronation-supination
  • * Ataxia
  • ** Assessment of gait
  • * Nystagmus
  • * Intention tremor
  • * Staccato speech
  • "intact finger-to-nose, gait WNL"

    Interpretation

    The results of the examination are taken together to anatomically identify the lesion. This may be diffuse or highly specific.
    General principles include:
    A differential diagnosis may then be constructed that takes into account the patient's background and present findings to include the most likely causes. Examinations are aimed at ruling out the most clinically significant causes and ruling in the most likely causes.