Symptoms · Symptom Library · FND presentation

Jerks and twitches

Sudden movements that startle you as much as everyone else

Also called: functional myoclonus · functional jerks · functional twitches

Functional jerks and twitches are sudden, brief involuntary movements. They can be infrequent or almost constant, and they often worsen when the nervous system is wound up or exhausted.

Safety. Urgent assessment if jerks come with loss of awareness, injury, breathing trouble, or a brand-new severe pattern.

How it can feel

  • Sudden jumps in an arm, leg, trunk or whole body.
  • Twitches that interrupt speech, walking or sleep.
  • A body that startles more easily than before.
  • Embarrassment when movements arrive mid-conversation.

Day to day

  • Holding cups, walking near edges, and public spaces can feel riskier.
  • Sleep fragmentation if jerks continue at night.
  • Avoidance of social settings after visible episodes.

Why this can be FND (simply)

These movements are produced by the nervous system without voluntary control. Variable intensity and distractibility can be part of the functional pattern.

What can help

  • Clear diagnosis and education.
  • Physiotherapy approaches for functional hyperkinetic movements.
  • Sleep support and reducing stimulant overload where relevant.
  • Anxiety about the jerk itself can become a second load — naming that helps.

This is information, not a treatment plan. Personal care decisions belong with you and your clinicians.

FAQs

Are jerks the same as tics?

They can look similar but are assessed differently. A clinician sorts the pattern; this page is information only.

Next steps