Neurological History and Examination

In finals and MRCP, an hour is allowed for history and examination. Many consultant physicians, and probably all neurologists, allocate an hour for a first consultation. The usual allotted time for a GP consultation is 10 minutes. Hence, if there is a neurological problem, even a very concise approach may be inadequate. The doctor has to decide whether to run late, and if so how late is acceptable, or whether to ask the patient to return with a longer appointment.

When taking a history we were told, "Listen to the patient. He is telling you the diagnosis." On the other hand, meandering needs to be led back to the relevant and certain aspects may need exploration and elucidation.

This is a very general article, attempting to cover all of neurological history and examination in a very brief space and so where a more specific aspect emerges, the reader is referred to that section with much more relevant detail. This may include diplopia and cranial nerve lesions, visual field defects, neurological examinaton of the upper limb and neurological examination of the lower limb. Mental state examination may also be an important consideration and is covered elsewhere.

There are certain aspects of the history of the presenting complaint that must be explored.

• What is the nature of the complaint?
• Was it sudden, rapid or gradual in onset? There may have been trauma.
• Is it static, deteriorating or perhaps there are exacerbations and remissions?
• Ask about walking and everyday living including fine skills such as writing or picking up small objects.
• Try to understand how it affects the patient's life.

There are certain terms that patients use that may need exploration.

• What do they mean by "giddy" or "dizzy"? Is there a feeling of rotation? Is there nausea? Do they have to sit down? Is there any precipitating factor?
• The term "numbness" is usually interpreted by doctors as meaning paraesthesia or loss of sensation. To the patient, it may mean that the limb does not do what he wants it to do and it really means weakness or paralysis.
• "Clumsy" is a term that the doctor may interpret as meaning lack of coordination but to the patient it may mean weakness or lack of fine motor skills. Coordination does require adequate power.
• When a limb, especially a leg, is described as "heavy", this often implies spasticity.

Enquire about other medical problems, past and present. A person in atrial fibrillation may be producing multiple tiny emboli. There may be vascular problems or recurrent miscarriage to suggest the antiphospholipid syndrome. There may be diabetes.

The systematic enquiry is very important here.

• Loss of weight and appetite may suggest malignancy and this may be a paraneoplastic syndrome.
• Gain in weight may have precipitated diabetes.
• Polyuria may suggest diabetes. Difficulty with micturition or constipation may be part of the neurological problem but was not volunteered in the general history. In men, enquire about erectile dysfunction.
• Enquiry about sleep may permit questions about mental status and any change in mental acuity. In a child, ask about performance at school. Mild memory loss and mini mental state examination are discussed elsewhere.
• Note smoking and drinking habits. Alcohol is a significant neurotoxin, both centrally and peripherally. Be aware that responses may be less than frank.
• Ask about drugs, prescribed, OTC and illicit. This includes complementary and alternative medicines.
• Ask about occupation and what it involves. There may be exposure to toxins. The job may involve driving but the patient has admitted to convulsions. He may work at heights or in a dangerous environment.

A cousin with Duchenne muscular dystrophy or Becker muscular dystrophy would be very important for a boy who cannot run like his peers. Huntingdon's chorea is unusual in that it is a familial disease that does not present until well into adult life. A family history of type 2 diabetes or vascular disease may be important.

A full neurological examination is very time-consuming and it is essential to direct attention to those aspects that have been revealed by the history. This may mean concentrating solely on that area but it is probably better to perform a very brief assessment of all areas with more detailed attention to specific areas.

With most examinations, the clinician will detect and interpret the signs. With neurological examination, especially of the sensory system, the doctor relies on the patient to interpret what he feels. He must be encouraged to report when there is a change in sensation or if anything feels different from normal. Very often there will not be an absence of sensation but a dulling or diminution and this is just as important. Comments such as, "I can feel it but it's not so sharp over there," are very useful.

The following is a quick and brief way of assessing the cranial nerves. It is recommended where no abnormality in them is suspected. Where history has suggested a problem, the article on cranial nerve lesions gives more detail.

• The olfactory nerve is usually tested by having bottles containing characteristic substances such as peppermint, coffee or heather and asking the patient to identify each in turn. If such bottles are not available, simply ask the patient if he has any problems with smell of taste. Remember that most of what we call taste is really smell.
• Hold the patient's head still with the left hand and hold out the extended right index finger about 40cm in front of the patient. Ask him to follow your finger with his eyes. The left hand makes sure that he does not turn his head. Move the finger up and down and left and right. There should be a full range of movements of both eyes. Then move the finger to the left and hold it there for several seconds whilst the eyes are observed for nystagmus. Repeat to the right. False positive tests for nystagmus can result from holding the finger too close and by moving it too far to the extreme of vision.
• Two important aspects of the optic nerve are visual acuiity and visual field. Visual acuity can easily be tested with Snellen type. If the patient normally wears spectacles this may be done with them on as it may be assumed that they give good correction and that what is important is any rapid deterioration in visual acuity. A small item, such as the top of a pen, may be used to test visual fields by confrontation. Sit about 40cm away from the patient and ask him to keep his eyes fixed on your nose. Hold the point hald way between you and move it around, asking him to say when it disappears from view. If you also fix on his nose then you can compare his response with yours, taking your own as normal.
• Take the ophthalmoscope and ask the patient to fix his gaze on something in the distance such as a picture on the wall and to ignore you. First shine the light on the eye and then remove it. The pupil should be brisk in its response. Then use the ophthalmoscope to examine the eye. Check that the optic disc is clear. Note the vessels of the retina and try to see the periphery. Repeat on the other side. It is not reasonable to assume that because one side is normal that the other side will be too.
• So far the cranial nerves I, II, III, IV and VI have been checked.
• Lightly touch each side of the face and ask if it feels normal and symmetrical. Ask the patient to clench his teeth. Both masseters should feel firm and strong. In this brief assessment it is fair to omit the corneal reflex.
• Ask the patient to give a broad toothy grin, demonstrating what you want. Is it full and symmetrical? Ask him to screw up his eyes. Gently try to prise them open. You should fail. If there is any facial weakness, ask him to raise his eyebrows. The upper motor neurone innervation of the muscles of the forehead is bilateral. Hence a lower motor neurone lesion will cause asymmetry but an upper motor neurone lesion will not.
• Either whispering or use of a high frequency tuning fork can give a very crude assessment of hearing.
• Assessment of the glossopharyngeal and vagus nerves is difficult. Ask the patient to open his mouth wide and to say, "Arhh". Phonation should be clear and the uvula should not move to one side. Then ask him to protrude his tongue and note any deviation. This checks the hypoglossal nerve.
• The accessory nerve supplies the trapezius and sternomastoid muscles. Ask the patient to shrug his shoulder up and try to push them down. In addition, you may ask him to push his head forwards against your hand. Both these movements should be very difficult to resist.

This gives a very basic but effective assessment of the cranial nerves in a very short space of time. Note that the nerves have not been assessed in numerical order but all have been included.

Neurological examination of the upper and lower limbs are covered in their own articles but some general points are made here. For examination of both the sensory and motor systems outside the cranial nerves, the patient needs to be adequately undressed.

As with the cranial nerves, a truncated examination is permissible in areas where no abnormalities are expected with greater attention to detail where findings on history or examination suggest pathology.

A logical format is required. A sensible routine would be to start cranially and work caudally bearing in mind the dermatome distribution of the body. After one section of the body, such as the arm, stop and test the other side. With all modalities, a difference between the two sides of the body is important.

Touch

Both light touch and pin prick are conducted along the same pathways. Light touch can be tested by using a light touch of the finger, a piece of cotton wool or a small brush. It is important to touch and not to stroke as moving sensation, such as rubbing and scratching are conducted along pain pathways.

Sharp sensation is often tested by using a disposable needle. The trouble is that they are very sharp and it is bad form to make your patient bleed. Neurologists used to prefer a hat pin. Not only are they less available these days, but it is important to use a new sharp instrument for each patient as breeching the skin may permit transmission of highly infectious diseases such as hepatitis C by a tiny amount of body fluid. An ordinary pin may be preferable to a disposable needle but a new pin must be used for each patient.

Some people would test first with sharp and then with light touch. A better technique may be to use both and to touch the patient with one or the other, saying to the patient, "When I touch you say sharp or soft."

Temperature

Testing for temperature sensation is often overlooked but it can be important. Tubes of hot and cold water may be used but an easier and more practical approach is often to touch the patient with a tuning fork as the metal feels cold. First touch the patient where sensation is thought to be normal and say, "Does that feel cold?" Then, when testing the limb, check that the patient is feeling the fork as cold and not just as pressure.

Proprioception

Proprioception is usually tested only on the great toes but it can be tested on the fingers too. Ask the patient to shut his eyes. Grasp the side of the toe between index finger and thumb. This prevents movement from being felt as pressure up or down. Move the digit up or down and ask the patient to tell you the direction of movement.

Vibration sense is conducted along the same pathways in the dorsal columns. It is often impaired in peripheral neuropathy. Strike a low frequency tuning fork and hold it against the medial malleolus. Ask the patient to tell you when it stops vibrating and then touch it to dampen it. This differentiates the feeling of vibration from simply the pressure of the fork. Vibration sense is often impaired in the elderly.

Two-point discrimination

When accurate assessment of sensation is required, two-point discrimination is tested. An instrument similar to a pair of dividers is used and the distance between the 2 points is adjusted. The patient is touched with either 1 or both points and he is asked to say "1" or "2" according to how many points he feels. With impairment of sensation, the two points have to be further apart to be distinguished. What is normal depends upon the sensitivity of the area being tested. Two-point discrimination is impaired in parietal lobe lesions.

Inspection

Start by looking at the patient. Do muscles look wasted? Is there asymmetry? An upper motor neurone (UMN) lesion will produce disuse atrophy but a lower motor neurone (LMN) lesion or myopathy will produce much more marked wasting. In both LMN lesions and myopathy there may be visible fasciculation. This is little twitches of groups of muscles. If you strike the affected muscle with a jerk hammer, it may induce fasciculation. The tongue has such intense innervation of small units that the very fine twitches are called fibrillation.

Tone

Increased tone occurs with UMN lesions and reduced tone with LMN lesions.

To test for tone in the upper limb, take the patient's hand and hold it with the elbow bent and the palm facing towards the shoulder. Ask the patient to relax and gently but firmly extend the arm whilst supinating at the same time. Replace it with flexion and pronation and repeat a few times to get the feel of the tone.

• Spasticity (UMN) produces a clasp knife rigidity in which there is resistance that suddenly fades as the arm is extended. This is said to be like opening a pen knife.
• Lead pipe rigidity is when there is a constant high tone resisting movement throughout the range. It is like bending a lead pipe and is typical of Parkinson's disease.
• In Parkinson's disease a tremor may be superimposed on the lead pipe rigidity to produce cog-wheel rigidity.

To test for tone in the lower limbs, ask the patient to relax and place your hand under his knee. Gently raise and lower it by about 10 to 15cm a few times, then, quite rapidly, raise it up until the knee is at about 90° and let it flop down. Throughout all this the heel will normally just slide along the couch. If it rises up in the air, tone is increased. Detecting hypotonia is rather more difficult. The leg feels floppy.

Power

As with sensation, test each group of muscles in a systematic order.

Muscular power can be graded 0 to 5, in which 0 is complete paralysis and 5 is full strength appropriate for the physique of the patient.

Eliciting tendon reflexes requires good technique. The commonest cause for an absent ankle reflex is failure to elicit it properly. An appropriate instrument is required. Small and compact instruments are sold but they are inferior to the traditional hammer. The head of the hammer should be a disc about 5cm in diameter surrounded by a firm rubber ring. The handle is about 30cm long. Traditionally it was made of cane but newer ones have a plastic handle that can unscrew. This makes it easier to fit into a case and the more flexible plastic gives a better "whip" than cane.

The handle is held near the end to benefit from the "whip" of the flexible material. The comparatively heavy head of the hammer is almost dropped on to the site to be struck. It is not a little jab but a "follow through" and if the tendon were not there the head would persue its course. It takes practice to get the correct degree of force.

How to elicit the various tendon reflexes is described in the articles on neurological examination of the upper and lower limbs. Tendon reflexes tend to be brisk when there is an UMN lesion and depressed in a LMN lesion or myopathy. Sometimes reflexes are graded on a scale of 0 to 5 with 0 being no response and 5 sustained clonus.

Clonus is most often demonstrated at the ankle but can be seen elsewhere. With the patient on his back, bend the knee to about 135° and externally rotate the hip so that the foot is pointing out. Take the foot in your hand with the ankle at about 90°. Give a sharp dorsiflexion of the ankle, stretching the calf, and there is a clonic response from that muscle. The intensity and duration will vary with severity.

Clonus can sometimes be demonstrated at the knee. With a straight leg, give a sudden, firm pull downwards on the patella to stretch the quadriceps. A clonic response occurs as with the calf.

Correct technique is also important for the plantar or Babinski test. Use a fairly sharp object such as the point of the tendon hammer or a key. Take the foot with one hand and firmly draw the object along the sole from just in front of the heel, on the lateral side, moving over to the medial side just before the metatarsal heads. Some people omit the last part and simply draw the object along the lateral side of the sole. This should be done firmly and surely and it should not need repetition. One reason is that it is very unpleasant if done properly and it is often best to apologize to the patient for having to have done such a test. The other reason is that repetition may produce an unreliable response.

An extensor plantar response indicates an UMN lesion except in infants in whom it is normal before myelination of the long pathways. The time of conversion to a flexor response usually indicates when they are ready to walk.

An extensor plantar response is a very important and significant sign. It may indicate a cerebral or spinal tumour, including compression from a prolapsed intervertebral disc. Nystagmus and an extensor plantar response are highly suggestive of multiple sclerosis. The finding of an extensor plantar response with an absent ankle reflex suggests a mixed UMN and LMN lesion. There are 5 classical causes.

• It can occur in motor neurone disease where there may be both UMN and LMN components.
• In vitamin B12 deficiency, both peripheral neuropathy and subacute combined degeneration of the cord may occur
• Nowadays we rarely see it in advanced syphilis with taboparesis
• Friedreich's Ataxia
• Syringomyelia

However, probably the commonest reason for this finding is failure to elicit one or both of the signs correctly.

The abdominal reflex is rather difficult to elicit properly. It involves lightly stroking 4 lines in a diamond shape around the umbilicus to produce reflex contraction of the abdominal muscles. It may be absent in obesity, where the abdomen is scarred and where it has been stretched as by pregnancy. It is also commonly absent in the elderly.

Muscular power and sensory input are inadequate without the ability to coordinate movement. Incoordination may be due to muscular weakness or failure of feedback as with loss of propriception but the cerebellum is very important in coordinating movement and cerebellar ataxia can occur when power and sensation appear intact.

There are a number of tests for coordination of the upper limb.

• Hold up your index finger in front of the patient and ask him to use his right index finger to touch your index finger and then to touch his nose. Get him to do this several times, moving your finger slightly as he does it. Repeat with his left index finger.
• Ask him to tap the dorsum of his hand with his fingers as quickly as possible. Repeat with the other hand.
• Dysdiadochokinesis is tested by asking the patient to hold up his hands with his palms facing forwards at about the level of his shoulders, and rapidly to pronate and supinate.
• Coordination of the lower limb may be tested by asking the patient, whilst lying on the couch, to run his heel down the opposite shin and then repeat on the other side.

Romberg test

Ask the patient to stand still with the heels together. Then ask him to close his eyes. If he loses his balance, the test is positive. Be ready to catch him if he stumbles.

Balance requires 2 of the following 3 inputs to the cortex:

• Visual confirmation of position
• Proprioceptive and vestibular input
• A normally functioning cerebellum

If the patient can stand still and balanced with eyes open but stumbles with eyes shut, there is likely to be a lesion in the cerebellum. This is a positive Romberg sign.

No neurological examination is complete without analysis of gait. It is said that a good neurologist will make the diagnosis by watching his patient enter the room. The consulting room is usually rather small, so ask the patient to step outside and to walk away from you for about 10 metres and then to turn around and walk back. With children it is sometimes worth taking them out to the car park and asking them to run up and down.

This is an enormous topic and abnormal gait and gait abnormalities in children both have their own articles. Also watch the patient as he rises from the chair and note any abnormality of movement. This may be the best sign of proximal myopathy.

There are certain aspects of examination that can be problematical.

• Make sure that apparent weakness is not due to pain, usually pain in joints. This can usually be overcome by testing isometric strength. Let the patient know that you expect a strong response and not a token effort when assessing strength. For a small doctor assessing a strong man, this can be challenging.
• When testing the facial nerve in an elderly person do not say, "Show me your teeth," as they are likely to remove their dentures and hand them to you.
• It may be that reduced vibration sense and absent ankle reflexes are not pathological in an eldery person.¹ The incidence of absent ankle jerks in the absence of obvious pathology does seem to rise with age² but performing the examination correctly may be more important.

A good knowledge of anatomy is essential for interpreting physical signs. The following two diagrams are very useful to help interpret neurological signs. Anatomy of the central nervous system, including the spinal cord, is also very important.