Temporal aspects include:

  1. Manner of onset (acute or insidious),
  2. Short-term variations in symptoms (diurnal, intermittent, or action induced)
  3. Longer-term variations in overall severity (static or progressive)3.

Dystonia phenomenology can evolve with disease progression or display momentary or daily variability in relation to voluntary actions, external triggers, compensatory phenomena, alleviating manoeuvres (gestes antagonistes) or the patient’s psychological state1.

There are four different patterns:

1.            Persistent.

Dystonia that persists to approximately the same degree throughout the day.

2.            Action-specific.

Dystonia that occurs only during a particular activity or task.

3.            Diurnal fluctuations.

Dystonia fluctuates during the day, with recognizable circadian variations in occurrence, severity and phenomenology.

4.            Paroxysmal.

Sudden self-limited episodes of dystonia usually induced by a trigger with return to pre-existing neurological state.

Paroxysmal dystonia is a specific entity, where the same trigger on different occasions might or might not induce an attack, and needs to be distinguished from dystonia which is always triggered by the same activity or action (ie task-specific dystonia).

In addition, the clinical presentation may vary over time, and this is particularly common in conditions in which dystonia is part of a syndrome (ie combined dystonia). For example, patients with SCA17 may present with a purely dystonic syndrome, which is followed by ataxia and other signs consistent with spinocerebellar ataxia. Similarly, patients with early-onset Parkinson disease frequently manifest initially with dystonia.