Continuous, slow, writhing movements of the limbs (distal and proximal), trunk, head, face, or tongue.

When brief, these merge with chorea (choreoathetosis). When sustained, they merge with dystonia (athetotic dystonia).

Restlessness. Inner component: bothersome urge to move. Motor component: movements made to relieve inner sensation.

Examples: crossing and uncrossing legs, caressing scalp or face, pacing floor, squirming in chair, picking at bedclothes.

Clinical setting: neuroleptic drug therapy, encephalopathy with confusional states, some dementias, Parkinson disease, levodopa toxicity.

Large-amplitude jerks, with flinging movements of limbs. Often unilateral (hemiballismus). Lesion usually in subthalamic nucleus.

Brief, irregular contractions; rapid, but not lightning-like.

Often affect individual muscles as seemingly random events, neither repetitive nor rhythmic (e.g., HD, Sydenham chorea).

Presumably disorders of caudate nucleus (see Chapters 109, 110).

Abnormal involuntary movements of one or multiple body regions. Most common appearance is of athetosis (see above). May be slow or fast. Most frequently continuous (see Chapter 117); sometimes intermittent (see “Paroxysmal Movement Disorders” below).

Usually evident at rest, increased by action, disappear during sleep (with exceptions).

Identified by appearance; EMG occasionally helps. Complex dyskinesias: choreoathetosis.

Sustained muscle contraction with twisting, repetitive movement, or abnormal postures.

Variably characterized by (a) sustained contraction of agonists and antagonists; (b) increase of involuntary contraction on attempted voluntary movement (“overflow”); (c) rhythmic interruption (dystonic tremor) of contraction when patient attempts to oppose them; (d) inappropriate or opposing contraction during specific voluntary motor actions (action dystonia); and (e) torsion spasm, which may be as rapid as chorea, but differs because it is continuous and includes twisting (see also Chapter 113).

Fast, lightning-like movements due to brief muscle contractions (Chapter 111). May be physiologic (e.g., hypnic jerks while falling asleep; hiccups), focal/diffuse, idiopathic/symptomatic, intermittent/rhythmic.

Due to continuous muscle firing; idiopathic.

Syndromes: neuromyotonia, encephalomyelitis with rigidity (spinal interneuronitis), stiff-limb syndrome, stiff-person syndrome.

Vague discomfort in legs, often described as formication (sensation of ants crawling under skin).