About Video

Patients with chorea have motor impersistence which is the inability to maintain sustained voluntary contraction of a muscle group at a constant level. Inability to apply steady pressure during handshake leading to a characteristic squeeze and release of grip has been termed milkmaid’s grip. Similarly, patients have difficulty maintaining forced eyelid closure or sustained tongue protrusion, known as the harlequin tongue or jack in the box tongue. Motor impersistence occurs independently of chorea and has been shown to be linearly progressive over the course of disease suggesting a potential role as a surrogate marker of disease progression. The reverse condition is known as motor perseveration, found in progressive supranuclear palsy.