[Neurology] Physical examination

Flow chart for a neurological examination

 

[Inspection]

The first clues for determining the neurological state of a patient are found by simply looking at them and around them. They may show signs of neurological disease including:

• Muscle wasting
• Involuntary movements
• Fasciculation
• Tremors 
• Unusual behaviour

It is also helpful to look around them at current medical interventions including:

• Intubation, ventilation
• Oxygen therapy
• Scars (past surgeries, may cause neurological problems, or may have attempted to treat them)
• Mobility aids, such as crutches, splints, wheelchairs
• Bedside medications

There is a useful mnemonic for inspection: SWIFT.

• Scars
• Wasting
• Involuntary movement
• Fasciculation
• Tremors

It is also very useful to observe general features such as:

• Age
• Sex
• Height and weight
• Hygiene / signs of self-neglect
• General health

Many patients show a classic set of signs on examination, and sometimes the diagnosis is strongly suggested by the appearance.
For example:

• Stroke (CVA/CVI) patients often have a flexed upper limb and an extended lower limb. This is called pyramidal weakness. In CVA, it is caused by an upper motor neuron injury in the nerves of the motor cortex in the brain.
• Parkinson's disease causes a "mask-like facies", meaning that patients usually have a lack of facial expression due to muscle rigidity. They are often hunched forward. There may be a "pill-rolling" tremor of the hands and forearms. They are slow to begin moving and their gait is shuffling with small steps.
• Huntington's disease is sometimes called Huntington's chorea because these patients exhibit choreiform movements. These patients are usually symptomatic in their 40s. These are involuntary repetitive jerky writhing movements which appear well-coordinated. Chorea means "dance". 
• Choreiform movements in children are more likely to suggest Sydenham's chorea, also called St Vitus' dance. This is caused by childhood infection with Group A beta-haemolytic Streptococcus.

 

[Muscle tone assessment]

Read more about the pathophysiology

Upper limb: Take the patient's hand in a handshake grip, ask them to relax as much as possible, and move the upper limb about to get a feel for the ease of passive movement. Make random, but purposeful movements and don't risk injury to the patient with excessively forceful movements. You should vary the speed of the movements, because sometimes muscles will "catch" and resist when you move the arm through a sudden quick movement. Remember to test arm supination and pronation. If the limb feels stiff or rigid it might be hypertonic.

Another useful test for upper limb hypertonicity is pronator drift. Ask the patient to close their eyes and stand with their arms raise to 90 degrees and their palms facing upwards. If the muscles are hypertonic, the pronator muscles will overpower the supinator muscles and the arms will slowly pronate. If the patient has their eyes open, they will see any pronation and resist it, because they want to follow your instruction to stand with the arms supinated.

Lower limb: With the patient lying supine on the bed, roll their lower limb back and forth. Watch the foot. If the limb is hypertonic, the foot will move with the leg as if it is fixed to it. If the limb is normal or hypotonic, the foot will flop about. If the lower limb is light enough you can try lifting it quickly at the thigh. If it is hypertonic the foot might lift off from the bed.

 

[Muscle power assessment]

Muscle power is tested by asking the patient to perform a set of movements with the affected limbs. These should be done first by the patient without any external resistance. If the patient can move the limb against gravity, then ask them to repeat the movements while providing resistance to movement. You must place you hand on the appropriate point of the limb when you provide resistance. If you are testing the deltoid and its ability to abduct the upper limb, you should place your hand on top of the upper arm, not on the forearm, as the elbow joint will separate the resistance from the muscle you are testing.

A key feature of medical signs is that they should be objective. For this reason, muscle power is usually rated 0-5/5 at each muscle. Each rating has a definition.

0: no motion seen
1: a flicker of muscle activity seen
2: muscle can contract but cannot overcome gravity to raise a limb
3: muscle can overcome gravity to raise a limb,, but cannot overcome weak resistance.
4: muscle can overcome weak resistance to raise a limb, but cannot overcome full active resistance
5: full muscle power

This will always be somewhat subjective, as one doctor might rate a patient as having 3/5 power while another rates it as 4/5. 4/5 in all limbs means general muscle weakness and this is often seen in many elderly and chronically ill patients.

 

[Deep tendon reflexes]

Read more about the pathophysiology
 
This is one that anybody could do if you bought a reflex hammer, but most medics are bad at this. The secret is to do a lot of practice on a lot of people. It is also helpful to remember some key features of the technique.

The most common mistake is to use the hammer like a typical hammer. It should actually swing like a pendulum. To allow this, you should hold it at the tail end, raise the head to 180 degrees, and let it swing downward to accelerate with it's own weight and hit the tendon. When a tendon is hit, the attached muscle should visibly contract. The limb will usually move as the muscle and its tendons pull on the bones.

It is also common for patients to increase their voluntary muscle activity and resist the reflex. You must instruct them to relax, and try to distract them. If all else fails, you can employ "accentuation manoeuvre", such as asking them to clench their teeth on the count of 3. Time the hammer swing so that it hits the tendon at the exact moment when they perform the manoeuvre.

An unusually strong (brisk) reflex may represent hypertonia in the tested limb. Some healthy individuals have brisk reflexes, but this is likely to be equal in all of their deep tendons. An absent or weak reflex may represent hypotonia.