Central Nervous System
Central Nervous System
As with all neurological patients, you will be more likely to pick up the diagnosis if you take a step back and look at the whole patient. Take some time to assess their facial expressions, speech, tremor, and posture. A common instruction at this station, with the patient seated on a chair is ‘Look at this patient, and examine as appropriate’. Candidates are often baffled, when given this instruction. Often the patients with Parkinson’s disease are given specific instructions to interlock the fingers of both hands, or place hands flat on their lap to mask the tremor. Picking up an expressionless face and low volume monotonous speech from the outset will provide useful clues to the diagnosis. If you are not sure at this stage, proceed to examining the gait. Once you are certain, that this is Parkinson’s disease, you may proceed to demonstrate the other features. 1. Patients with Parkinson’s disease have characteristic expressionless facies (hypomimia), often described as ‘mask-like’. This is a manifestation of bradykinesia. There is a reduced blink rate. The glabellar tap (Myerson’s sign) is an unreliable sign and is not recommended in the examination. This involves tapping the patient’s forehead repeatedly. Normal subjects will stop blinking, but in Parkinson’s disease, the patient will continue to blink. The patient may be drooling saliva (resulting from dysphagia and sialorrhoea-due to autonomic dysfunction) 2. Patients may have soft speech (hypophonia). This is also a manifestation of bradykinesia, and characteristically, the speech is low-volume, monotonous and tremulous (appears slurred). 3. Blepharoclonus is tremor of the eyelids. This will only be demonstrated if the eyes are gently closed, as opposed to tightly closing the eyes. 4. The classic tremor is present at rest and asymmetrical (more marked on one side). It is classically described as being 4–6Hz and is the initial symptom in 60% of cases, although 20% of patients never have a tremor. The tremor may appear as a ‘pill-rolling’ motion of the hand or a simple oscillation of the hand or arm. It is easier to spot a tremor if you ask the patient to rest their arms in their lap in the semi-prone position.
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