Reference was made in Chaps. 3 and 4 to weakness, akinesia, and bradykinesia as manifestations of corticospinal and extrapyramidal disease. Disorders of these parts of the motor system interfere with voluntary or automatic movements, much to the distress of the patient. But motility and activity can be impaired in more general ways in which the overall tone of the motor system is enhanced or diminished. One such disorder is a lack of conation, or impulse. These terms emphasize that the basic biologic urges, driving forces, or purposes by which every organism is motivated to achieve an endless series of objectives. Indeed, motor activity is ostensibly a necessary and satisfying objective in itself, for few individuals can remain still for long before they become fidgety or doodle, and the severely retarded apparently obtain gratification from certain rhythmic movements, such as rocking, head banging, and hand flapping. These are all presumed to be driven by mental impulses. As discussed in Chap. 4, tics and compulsions apparently also represent the fulfillment of some psychic urge.
However, in reference to the confusional states, a quantitative reduction in all spontaneous activity, that is, in the amount of activity per unit of time, is one of the most frequent manifestations of cerebral disease. An important aspect of this state, called abulia, is a prominent delay in producing movement, speech, ideation, and emotional reaction, together observed as a kind of apathy. The terms bradyphrenia, and “psychomotor retardation,” referred to above may be a related or perhaps identical phenomena. With certain cerebral diseases the disinclination to move and act may reach an extreme degree, to a point where a person who is wide awake and perceptive of the environment does not speak or move for weeks on end (akinetic mutism). Such patients seem indifferent to what is happening around them, and unconcerned about the consequences of their inactivity.
Abulia and akinetic mutism must be distinguished from catatonia. Kahlbaum, who first used the term catatonia in 1874, described it as a condition in which the patient sits or lies silent and motionless, with a staring countenance, completely without volition and without reaction to sensory impressions. Sometimes there is resistance to the examiner’s efforts to move the patient, or the patient repeats certain movements or phrases hour after hour. If the limbs are moved passively, they may retain their new position for a prolonged period (flexibilitas cerea, or “waxy flexibility”), but more often there is no actual motor rigidity except that of voluntary resistance, termed paratonia. Profound depression or other psychosis is the usual cause of catatonia. The psychomotor retardation of psychosis may be so profound that the patient makes no attempt to help himself in any way and ultimately starves unless fed with a nasogastric tube.
Less easy to understand is a form of “lethal catatonia,” originally described by Stauder, in which the completely inert catatonic patient develops a high fever, collapses, and dies. In some respects, this state resembles the neuroleptic malignant syndrome, an idiosyncratic consequence of intoxication with neuroleptic drugs. In abulia, catatonia, and depression, the mind is usually sufficiently alert to record events and later to recount them, which differentiates these states from stupor and the vegetative state. But these distinctions are not always valid, for there are catatonic schizophrenic and depressive patients who could not recall what had happened during the period of illness.