Between the waves a movement, so to speak, there is bizarre posturing of the body and limbs. After a time contractures of the muscles, especially of the feet and torsion of the pelvis become permanent features, in addition to the movement. Myoclonus is a sudden, regular or irregular contraction of a muscle which does not usually produce movement. It appears as if the muscle responded to a faradic current. These spasmodic Contractions generally are observed in the limbs but may be seem in the body and face. Hiccup is a spasmodic myoclonus of the diaphragm.

Aside from the fact that localized myoclonus may occur as a symptom or sequel of encephalitis (especially the abdominal muscles) it may be widespread as in paramyoclunos multiplex of Friedrich, and occur in association with the convulsive state in the condition known as Unverricht’s myoclonus epilepsy.

Finally one may observe the generalized tonic and clonic muscle spasms classed under convulsion. True convulsive seizures are accompanied by unconsciousness. At first they are fairly regular, tonic, in which the whole body is rigid; later they become intermittent and clonic. The localized convulsive spasms, limited to the face or one limb or half of the body, are not as a rule attended by unconsciousness though this may ultimately supervene and pareses of the muscles which were the seat of the localized fits remain as temporary or permanent sequelae. The titanic spasm or cramp, during which the patient is not unconscious, is manifested by rigidity extension of the limbs and obstetric position of the hand: adduction of the fingers and thumb flexion at the metacarpophalangeal joints and extension of the distal phalanges and extension of the lower extremities. The tonic or cerebellar fits, which may be unilateral or bilateral, are also sudden in onset and accompanied by unconsciousness.