COGNITIVE FUNCTION

Level of consciousness

Organic states may lead to confusion in which there is disorientation in time, place and person, with feelings of bewilderment. In clouding of consciousness there is similar disturbance of perception and attention with subsequent amnesia. When there is also marked anxiety a state of delirium exists when there may also be hallucinations, paranoid ideation and consequently overactive or aggressive behaviour.

Coma

Profound loss of consciousness due to organic cause is the deepest level of loss of responsiveness and may be associated with loss of all responses and even reflexes.

Stupor

A state of relative non-responsiveness to the environment which may be part of precoma in organic disturbance, electrolyte disorders, mid brain tumours or hypoglycaemia. The psychogenic type (depressive or catatonic or hysterical) is associated with full awareness of environment.

Patient is immobile, mute, while his eyes may follow external object. EEG may be useful in diagnosis.

Attention

In the normal state this involves a central focus of high intensity with extension to include a variable amount of peripheral material in a less clear way. Both intensity and extent of attention may be impaired by psychological and organic factors, often in a fluctuant way.

Variability is a marked feature of early organic impairment. DistractiiIity is common in hypomanic euphoria. Intense preoccupation with a single theme may occur in depression (guilt) or obsessional states (phobic objects or rituals).

Selective inattention is similar to the defence of denial with avoidance of matters that generate anxiety.

In Hypnosis, there is restricted awareness with intense focus on one area o consciousness and heightened suggestibility.

Orientation

The ability to recognise one's surroundings and their temporal and spatial relationship to oneself, or to appreciate one's relatonship to the environment requires adequacy of exteroceptive data, effective recent correct inteIIectal adjustment to outer reality (level of consciousness, freedom from delusional thinking).

Concerns

Time: (hour, day, week and year).

Place: (present location, its nature, home address, reasons for being in present situation).

Person: (Identity of self and others).

May be related to organic disorder but psychogenic factors may also lead to disorientation as in hysterical dissociation.

Memory

Registration may be Impaired by any reduction in consciousness and awareness, alcohol, drug induced or other organic disorders of the central nervous system or psychogenic factors including severe anxiety and panic states.

Retention

Extremely rapid decay in 'curve of forgetting' may occur in certain organic brain diseases, e.g. Korsakoft's Psychosis. In Alzheimer's disease there is a profoubd impairment of new learning ,but in the early stages the rate of forgetting, once information is acquired, may be normal.

Recall

Amnesia is the partial or total inability to recall past experiences. Psychogenic impairment usually related to emotional difficulties, selective for painful events, either recent or distant, and memories may return. In gross hysterical state there may be global amnesia involving all past events and identity. May be associated with physical flight to new and strange surroundings (fugue). Organic amnesia may be irreversible, usually concerns recent events and may leave remote memory intact and not specifically selective for emotionally traumatic events. Important to note that typical hysterical amnesia may occur in addition to underlying organic brain disorder, and may even be precipitated by it.

Recognition

A sense of familiarity with regards to recalled material. In mild nominal dysphasia words may be correctly recognised and identified even though their spontaneous recall is not possible.

Deja vu

This is an illusion of recognition in which a new situation is incorrectly regarded as a repetition of a previous memory.

It is Common in normal anxiety states or epileptic aura.

Jamais vu

It is an illusion of failure to recognise familiar situations.

Confabulation

It is the filling of gaps in memory by false imagined experiences which the patient believes to be true.

Dysphasia and aphasia

These are specific memory disorder for words and language related to organic brain disturbance in the dominant temporal lobe (speech centre), and contiguous areas.

Intelligence

Intellinence is the ability to solve problems, which require logical thought processes.

There is considerable normal individual differences in accuracy, speed, level of problem complexity and flexibility as well as originality of solution.

Routine clinical assessment of intelligence permits only approximate estimation. Poor educational experience, sociocultural factors or mental illness must always be allowed for before a judgement is made. Standardised intelligence tests are highly reliable and should always be used when routine clinical assessment suggests that further investigation of intelligence levelis needed.

Intelligence quotient (I.Q.) = mental age (BineSimon scale) x 100 chronological age