My mum looks after my dad, who has been living with Parkinson’s for about 20 years. He shakes and twists his body and head a great deal. My mum notices that he shakes less, or hardly at all, in certain situations, such as when they’re seeing a doctor or when they have a visitor at home for a cup of tea. As soon as they’ve finished the doctor’s appointment or the visitor has left, he starts shaking very badly. She wonders how this can be, she says.

Firstly, it’s a bit unclear what kind of movements you mean. Regular tremors are a symptom of Parkinson’s, but twisting movements of the body and head sound more like hyperkinesia, which is a side effect of Parkinson’s medication. However, it can be said that both types of movement can be overcome to some extent through willpower, at least for short periods. Some movements are exacerbated by stress, but focusing can, despite stress, reduce the movements. It is difficult to say why this is the case, but ‘body and mind’ are, of course, interconnected, and temporary moods can affect the brain’s signals to the motor control system. /Dag Nyholm