Disturbed State of Consciousness

Description of Disturbed States of Consciousness

The noble researcher Aggernaes (1975) offered a rather convoluted definition of a ‘disturbed state of consciousness (DSC):

a state in a person in which he has no experiences at all, or in which all of his experiences are deviant, concerning other or more qualities than tempo and mood coloring, from those he would have under similar stimulus conditions in his habitual waking state.

While sensory processes are obviously an essential first step in adaptive interaction with the world, sensation alone does not produce a state of intact consciousness. In the clinical as well as the research setting, consciousness is evaluated by observing the presence or absence and the quality of motor response to stimulation.

Does the patient reply or turn his head or shift his gaze when we call his name?

If he has failed to show evidence of awareness of our presence, does he withdraw when we inflict pain with a needle or a forceful squeeze of an extremity, or does he at least emit the primitive grimace and grunt?

At times autonomic motor responses may be used, as in observing respiratory changes or flushing in response to stimuli, and in special situations the polygraph has been employed to make subtle assessments of state of consciousness. The electroencephalogram is also used on accasion—an excepton to the statement that motor responses provide the criterion of consciousness.

But by and large we depend upon somatic motor behavior viewed in the setting of the stimulus situation. There are some problems with this indicator of consciousness. It has been reported, for example, that patients completely paralyzed by curarization (a treatment sometimes used to control contractions in severe tetanus), although they are completely unresponsive and therefore, from a motor standpoint, quite indistinguishable from patients in coma, may be acutely aware of events taking place around them and able to report these memories upon recovery.

Despite inherent problems of definition and assessment, the clinical evaluation of level of consciousness does focus upon the patient’s appreciation of the significance of sensory stimuli, as reflected in his motor responses. This focus upon perceptual interaction with the world has meant that, in clinical usage, the terms consciousness and sensorium are often employed interchangeably.

In the state of full consciousness, the individual is capable of responding to a wide range of types and intensities of stimulation. He does, of course, attend to some more than others.

This capacity for selective attention-inattention is, in fact, an important indicator of the conscious state. Selection obviously involves appreciation of the relative importance and significance of various stimuli, a perceptual process one or more steps removed from peripheral sensation.

Distractibility Opens in new window, the inability to maintain attention in the face of multiple stimuli, is often an important clinical sign of impaired consciousness. A balance between attention and a capacity to shift focus is clearly the most adaptive state. The fully conscious cook will ignore the gently simmering pot but shift attention to it immediately when it begins to boil over.

It will increase our understanding of the definitions of consciousness if we consider its absence as impairment. One obvious choice for the condition at the other extreme from full consciousness is deep sleep.

Although the sleep-wakefulness axis is important in the total behavioral life and for understanding certain areas of psychopathology, it does not represent impairment of consciousness.

Although consciousness is unquestionably reduced during sleep, significant changes in stimulus conditions will usually produce prompt awakening.

Note also that what is ‘significant’ will vary from person to person: a mother will often wake at the first sound of her baby’s crying. Clearly the sleeping person is still in some adaptive contact with the environment.

There are, moreover, converging lines of neurophysiological evidence suggesting that the CNS mechanisms mediating sleep are not those affected in the disturbances of consciousness characteristic of organic brain disease.

In certain pathological states (in contrast to normal sleep), even the most intense stimulation — even stimuli which signal grave danger to the organism—elicits no reactions to suggest arousal or a return to consciousness.

The application of intense pain is a classic test to determine the presence and depth of the comatose condition. Between coma and full wakefulness there is a continuum of levels of consciousness which may often be observed in the same patient over a period of time.

The stages of this wakefulness-coma axis are, for clinical purposes, usually given as:

• consciousness  Opens in new window,
• confusion  Opens in new window,
• clouding  Opens in new window,
• stupor  Opens in new window, and
• coma  Opens in new window.

Most abnormal states of consciousness show a lowering or diminution of consciousness. However, heightened consciousness occurs in which there is a subjective sense of richer perception:

1. colors seem brighter and so on;
2. there are changes in mood, usually exhilaration, perhaps amounting to ecstasy;
3. there is subjective experience of increased alertness and a greater capacity for intellectual activity, memory and understanding.

There may also be synesthesia Opens in new window (a sensory stimulus in one modality resulting in sensory experience in another, for example hearing a fingernail drawn down a blackboard results in a cold feeling down the spine). Such states, both heightening of consciousness and synesthesia, may occur in normal, healthy people, especially in adolescence or at times of emotional, social or religious crisis: when falling in love, on winning a large sum of money, at sudden religious conversion and so on.

Heightened awareness is not uncommon with certain drugs, notably with the hallucinogens, for example lysergic acid diethylamide, and central nervous system stimulants, for example amphetamine. A similar state of awareness may occur occasionally in early psychotic illness, especially mania, or less often in schizophrena.