DISORDERS OF MEMORY   Seven stages in memory (Welford): ·         Adequate perception, comprehension and response to the material to be learned. ·         Short-term storage. ·         Formation of a durable trace. ·         Consolidation. ·         Recognition that certain material needs to be recalled. ·         Isolation of the relevant memory ·         Using the recalled material.     THE AMNESIAS Psychogenic amnesias ·         Anxiety amnesia - seen in: -          Psychogenic reactions -          Morbid anxiety, particularly in depressive illnesses. ·         Katathymic amnesia – a set of ideas which are disturbing when conscious are repressed in an attempt to avoid the affect which they would otherwise produce. Seen in: -          Hysteria -          Normal persons ·         Hysterical (dissociative amnesia) – there is a complete loss of memory and loss of identity, but the pt. can carry out complicated patterns of behaviour and is able to look after himself. Is often associated with a fugue or wandering state.   Organic amnesias ·         Acute coarse brain disease: Poor memory is due to disorders of perception and attention and the failure to make a permanent trace. Retrograde amnesia: amnesia which embraces the events just before the injury; is the result of disturbance of the short-term memory. Post-traumatic amnesia: the period between loss of consciousness and the appearance of full awareness and memory; duration is directly related to the severity of the head injury. Anterograde amnesia: the pt. is apparently fully conscious, but has no memory for the events which occur; is the result of a failure to make permanent traces. Seen in: -          Alcoholic ‘blackout’ -          Delirium -          Twilight state due to epilepsy -          Pathological drunkenness Transient global amnesia: -          A sudden onset of retrograde amnesia covering a period of a few days upto several years. -          Perception and personal identity remain normal -          An anterograde amnesia continues until recovery (upto several hours) -          The amnesia subsequently shrinks to a period of half to five hours. -          In some patients there is evidence of ischemia in the territory of the posterior cerebral circulation. -          The immediate cause is probably from bilateral temporal or thalamic lesions.   ·         Subacute coarse brain disease: The pt. may have a retrograde amnesia which stretches back over a no. of years before the onset of the disease; is due to destruction of memory traces. The amnestic state: -          There are 3 faults: difficulty in forming permanent traces, difficulty in recall and thought disorder. -          There is disorientation for place and time, euphoria and confabulation. -          Is related to damage to the floor and walls of the third ventricle and those parts of the brain, eg. temporal lobes, closed linked to them. -          In some pts. there is a complete loss of ‘impressibility’ (registration of new memories). -          The disorder of thinking is an inability tom change set, called tramline thinking. Once thought is proceeding in a given direction it continues in that direction for an unnecessarily long time, and instead of being corrected by the incoming information it distorts the information that is getting registered and makes recall difficult.   ·         Chronic coarse brain disease: -          The amnesia extends over many years. -          Ribot’s law of memory regression: in dementing illnesses the memory for recent events is lost before the memory for remote events.       DISTORTION OF MEMORIES ·         Disorders of recall (paramnesias) ·         Distortions of recognition   Disorders of recall ·         Retrospective falsification ·         Retrospective delusions ·         Delusional memories ·         Confabulations   ·         Retrospective falsification: the subject modifies his memories in terms of his general attitudes. Seen in: -          Normal people (degree of retrospective falsification is inversely related to the degree of insight and self-criticism of the individual). -          Hysterical personality -          Depressive illness -          Agitated depression -          Mania   ·         Retrospective delusions -          The pt. dates back his delusions. -          Could be regarded as delusional retrospective falsification. -          Seen in Schizophrenia   ·         Confabulations -    A false description of an event, which is alleged to have occurred in the past. -    Could be influenced by the examiner. -    Could be explained as a result of ‘tram-line’ thinking. -    Some amnestic patients will construct comp[lately false explanations of TAT cards based on one false interpretation of a detail. -    Seen in organic states, hysterical psychopaths, amnestic syndrome, and chronic schizophrenia -    Some chronic schizophrenics confabulate, producing detailed descriptions of fantastic events which have never happened. Leonhard suggests that these pts. have a special form of FTD which he calls ‘pictorial thinking’. Bleuler preferred to them ‘memory hallucinations’, since the memories are false and unchangeable. But the ‘hallucinatory flashbacks’ which occur in temporal lobe epilepsy may better merit the designation ‘memory hallucinations’.       DISORDERS OF RECOGNITION ·         Déjà vu and deja vecu ·         Misidentification   ·         Déjà vu -          The subject has the experience that he has seen or experienced the current situation before. -          The sense of recognition is never absolute. -          Seen in normal people and in temporal lobe lesions ·         Misidentification -          Positive misidentification -          Negative misidentification   Positive misidentification -          The pt. recognizes strangers as his friends and relatives. -          Some patients assert that all of the people whom they meet are doubles of real people. -          Seen in  confusional states, acute schizophrenia (can be based on a delusional perception) and chronic schizophrenia (false identity to every fresh person met) ·         Capgras syndrome: pt. insists that a particular person (or persons), usually somebody with whom the pt. is emotionally linked, is not the person he claims to be but is really a double; is often accompanied by depersonalization and occurs in a paranoid setting. Seen in schizophrenia (commonest cause), involutional depression and very hysterical women ·         ‘Amphitryon illusion’: patients believe that their spouses are doubles. ·         ‘Sosias illusion’: patient believes that other people as well as the spouse are doubles. ·         Syndrome of Fregoli: the patient identifies a familiar person (usually his persecutor) in various strangers, who are therefore fundamentally the same individual.   Negative misidentification -          The pt. denies that his friends and relatives are people whom they say they are and insists that they are strangers in disguise. -          Could result from an excessive concretization of memory images. Back to Top