Are tremors likely after a stroke?

Post Stroke Clonus
A fellow caregiver asked...

What are the chances of a stroke survivor having tremors post-stroke?

Expert Answer

James Castle, M.D. is a neurologist at NorthShore University HealthSystem (affiliated with The University of Chicago) and an expert on strokes.

The answer to this question depends on what you mean by "tremors".  That term makes me think of two different possibilities - seizures or clonus.

Seizures are caused by abnormal brain electrical activity.  They can occur in a few percent of patients after a stroke (from scarring on the surface of the brain), and typically cause convulsive activity of the arm or leg affected by the stroke.  The convulsions are independent of positioning of the limb, and can be associated with change in consciousness.  They are diagnosed by EEG testing, and are usually very treatable.

Clonus is a completely different tremor.  It is caused by lack of inhibition of the lower spinal cord.  I would also estimate that this effects a few percent of post-stroke patients.  Clonus typically causes a position-dependent continuous reflex movement of the leg more commonly than arm.  This can often be brought out by quickly flexing the foot at the ankle (toward the head).  This type of tremor is much more difficult to treat.  It would require the use of Botulinum toxin in the affected muscles, or muscle relaxants.