Myoclonus, sudden brief jerks involving groups of muscles, is more common in juvenile-onset
HD, where it may be mistaken for a seizure.
Like chorea, myoclonus may not be disabling or particularly distressing, but may respond
to treatment with clonazepam or divalproex sodium if treatment is necessary.
Tics are brief, intermittent stereotyped movements such as blinking, nose twitching, head
jerking, or transient abnormal postures.
Tics which involve the respiratory and vocal apparatus may result in sounds including
sniffs, snorts, grunts, coughs, and sucking sounds.
Patients may be unaware of vocal tics, but family members may find the incessant noises
grating. They should be helped to understand that the tics are not under voluntary control.
Tics generally do not by themselves require treatment, but may respond to neuro-leptics,
benzodiazepines, or SSRIs.
Epilepsy is uncommon, though not unheard of, in adults with HD, but is said to be present
in 30% of individuals with juvenile-onset HD.
A first seizure in an HD patient should not be attributed to HD without further evaluation
as it may be indicative qf an additional neurologic problem, such as a subdural hematoma sustained in a fall.
The workup of a first seizure should include a complete exam, laboratory studies to rule
out an infection or metabolic disturbance, an EEG, and a brain imaging study.
The treatment of a seizure disorder in a person with HD depends on the nature of the seizures.
In the juvenile HD patient, myoclonic epilepsy or other generalized seizures may suggest divalproex sodium as a first treatment
Although seizure management in HD is not usually difficult, for the occasional patient
seizure control is quite difficult to achieve, requiring multiple medications or specialized referral.