In the OSCE situation (or in clinical practice) you may be asked to perform an examination to elicit the signs of Parkinson’s disease. In this case you don’t have to do a full neurological exam, and the key points are summarised below.
The history is perhaps more important for Parkinson’s than for other conditions. Yu should try to keep the questions open to begin with to see how much information is volunteered. If not much is forthcoming then you may want to ask closed questions. Particular things to look out for include:
- General lethargy and tiredness
- Problems using tools
- General problems with dexterity
- ‘Freezing’ – often whilst walking the patient may suddenly stop. This is particularly apparent at times when hesitation is normal, e.g. when turning, or when going through a doorway
- Difficulty rolling over in bed
- Ask them about their handwriting – Typically it becomes smaller, and more spidery. You may want to ask them to write their name and address to show you their writing.
- Anosmia – start by asking if they have noticed any changes in their sense of smell. See below for how to examine
- Violent dreams – patients with PD may act out their dreams whilst laid in bed – particularly violent ones. This may involve arm swinging and legs kicking. Often their partner will sleep in a different bed
- Visual hallucinations – usually these are not distressing, and many patients find them intriguing. For example, may involve seeing animals walking around the room, or seeing a hat stand, and thinking it is a person.
Parkinson’s disease is often a spot diagnosis – just by seeing a patient walk into the room you may be able to give a diagnosis.
Keep to a system – in this case we will start at the top of the body and work down.
Head / neck & cranial nerves
- Look for features of reduced facial expression / plain face
- Speech – tone become monotonous and volume is often reduced (hypophonic)
- Anosmia – only recently recognised as a feature. You can start by asking basic questions – e.g. if they can smell when they’re cooking. To do a proper clinical test do not use the bottles of smells! A more modern technique is to use scratch cards which have more subtle, everyday smells.
- Increased tone
- Rigidity – remember – rigidity and spasticity are NOT the same thing!:
- There is constant opposition to passive movement – we say that the resistance is not velocity dependent.
- Upper limb – the resistance is worse on extension
- Lower limb – the resistance is worse on flexion
- Sometimes referred to as ‘lead pipe’.
- The resistance is velocity dependent. There is an initial strong opposition to passive movement, but once this resistance is overcome, the limb will move freely for the rest of that one particular movement. Imagine it like you have just untightened a really tight screw.
- In PD, the rigidity is often referred to as cogwheel rigidity. This is best elicited at the wrist. Passively roll the patient’s wrist joint. As you do so, notice how at several points during one revolution, there is a resistance. This is the cogwheel rigidity.
- If you cannot elicit this effect, you can extenuate it, by asking the patient to actively rise and lower their contralateral arm into the air as you roll the opposite wrist.
- You may also elicit cogwheel regitidy / classic rigidity by:
- Felxing/extending the arm at the elbow
- Pronation/supination of the hands
- Check dexterity – this is another good test to elicit PD. Ask the patient to oppose their thumb and forefinger. Ask them to repeat this action, perhaps for up to 1 minute. As the patient repeats the action, it may become more and more difficult, and the size of the movement becomes gradually reducing. You may repeat the test, recruiting each finger in turn.
- Check handwriting – this is particularly useful if you have previous examples of the handwriting, but you can also ask the patient if they think their handwiritng has changed. It is likely to become smaller, and more spidery.
- Reduced arm swing
- Reduced length of steps
- Can be unilateral or bilateral
- ‘slow shuffling gait’
- May find it hard to initiate walking, and may stop abruptly
- Turning may be difficult and slow
To perform this test correctly, you shouldn’t actually tell the patient what you are going to do, but this might be dangerous.
You should ask the patient to stand, at ease. Stand behind the patient, and put your hand on the patient shoulder. Then quickly and firmly, pull back on the shoulder. In a normal individual, they might take 1 or 2 steps backwards to stop themselves falling. In PD, it may take 4-5 steps before they come to rest again.