Severely confused and inattentive persons are unable to do more than carry out the simplest commands, and these only inconsistently and in brief sequence. Speech may be limited to a few words or phrases; or the opposite pertains—namely, some confused individuals are voluble. They give the appearance of being unaware of much that goes on around them, are disoriented in time and place, do not grasp their immediate situation or the predicament of their own confusion, and may misidentify people or objects. These illusions may lead to fear or agitation. Occasionally, hallucinatory, illusionary, or delusional experiences impart a psychotic cast to the clinical picture, obscuring the deficit in attention.
Many events that involve the confused patient leave no trace in memory; in fact, the capacity to recall events of the past hours or days is one of the most delicate tests of mental clarity. Another is the use of “working memory,” which requires the temporary storage of the solution of one task for use in the next. A deficit in working memory, which is a common feature of the confusional states, can be demonstrated by tests of serial subtraction, and the spelling of words (or repeating a phone number) forward and then backward. Careful analysis will show these defects to be tied to impaired registration of information rather than to a fault in memory. These phenomena again betray inattention as central features of most confusional states. As already stated, the observed behavior of a confused person transcends inattention alone. It may incorporate elements of clouded interpretation of internal and external experience, and an inability to integrate and attach symbolic meaning to experience (apperception). The degree of confusion often varies from hour to hour and one time of day to another. It tends to be least pronounced in the morning and increases as the day wears on, peaking in the early evening hours (“sundowning”) when the patient is fatigued, and environmental cues are not as clear.
In most current medical writings, particularly in the psychiatric literature, the terms delirium and confusion are used interchangeably, the former connoting nothing more than a nondescript confusional state. However, in the syndrome of delirium tremens (observed most often but not exclusively in alcoholics), the vivid hallucinations; extreme agitation; trembling, startling easily, and convulsion; and the signs of overactivity of the autonomic nervous system suggest to us that the term delirium should be retained for this type of distinctive confusional syndrome (elaborated in Chap. 19).
As commented earlier, a relationship between the level of consciousness and progressively disordered thinking, namely confusion, is evident as patients pass through states of inattention, drowsiness, confusion, stupor, and coma.
Drowsiness denotes an inability to sustain a wakeful state without the application of external stimuli. Mental, speech, and physical activity are reduced. The state is indistinguishable from light sleep, sometimes including slow arousal elicited by speaking to the patient or applying a tactile stimulus. Furthermore, in distinction to stupor discussed later, drowsy individuals sustain alertness for at least some brief period, without the further necessity of external stimuli. As a rule, some degree of inattentiveness and mild confusion are coupled with drowsiness, both improving with arousal. The patient shifts positions somewhat naturally and without prompting. The lids droop; there may be snoring, the jaw and limb muscles are slack, and the limbs are relaxed.