Amnesic Syndrome Amnesia
Hypothetical amnesic syndrome single case intervention: Clive Wearing
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Amensia – Amnesic Syndrome
Amnesia is a general, classically used term essentially to describe the partial or total loss of memory. Due to the complexity of human memory functioning, several different types of amnesia exist, in particular, Amnesic Syndrome (A.S.) which, in its most coherent, is a cluster of amnesic symptoms. Amnesic syndrome is characterised by the permanent memory impairment which can occur in anterograde form – the syndrome’s defining feature – and retrograde form.
Unlike general amnesic condition, the diagnostic origin of A.S. excludes degenerative disorders, for example Parkison’s; transient amnesias; and psychogenic disorders. The aetiology of A.S. include those brought on by (direct or indirect) injury to the brain and damage to any number of neuroanatomical locations responsible for memory functioning, namely subcortical areas – the diencephalon, a major region of the brain that includes the third ventricle, thalamus, hypothalamus, and pituitary gland; and also cortical areas – covering the medial surfaces of the temporal lobe, especially the hippocampus.
Understanding the effects of this damage is possible in no small part to using the modular memory system approach and observing the pattern of preservation and loss – in other words, what the patient is and is not capable of. It is understood that long term memory (LTM) is structured as to distinguish declarative memory – of what we know to be as ‘fact’ – from less explicitly accessible memory functioning such as those implicitly stored and that which is not pertaining to factual information, referred to as non-declarative memory.
Aggleton & Brown (1999) reported that both the subcortical and cortical locations, as mentioned above, are components of the same memory system concerned with the explicit, declarative memory. This declarative memory is made up of the subcategories episodic – personal events one experiences; and semantic – relating to vocabulary, language ability and object recognition.
It is therefore clear that the damage suffered to part or all of these areas of the brain would largely affect the declarative memory of a patient, whilst leaving the implicit, non-declarative memory relatively unimpaired. This is true in cases of both anterograde and retrograde amnesic syndrome.
There are also several non memory related characteristics of amnesia which appear in A.S., degrees of which depend on the origin of the syndrome, for instance the location of injury and which parts of the brain are affected. Characteristics include orientation, intellectual deficit and confabulation. Confabulation, sometimes referred to as ‘islands of confabulation’, describes the attempts made to rationalise memories (or voids in memory) in order to make sense to the self and others, which may involve the production of false information.
Single Case: Clive Wearing
Clive Wearing is considered by many to be the most sever case of amnesia. Once a renowned and eminent musician and musicologist, Clive was struck by an inflammatory brain infection – herpes encephalitis, in March of 1985. An initial CT and subsequent MRI scan reported major and significant damage to the left temporal lobe, also extending into the inferior and posterior frontal lobe as well as damage to the medial side of the right temporal lobe. This was accompanied by indications of involvement of the left lateral ventricle and third ventricle – part of the diencephalon, along with the almost complete destruction of the hippocampus.
It is believed that these areas of damage are the cause of several behaviours Clive Wearing exhibited and continues to do so today. It is well reported that Clive (CW) has severe episodic memory dysfunction, resulting in retrograde amnesia for virtually the whole of his adult life and much of his childhood along with anterograde amnesia demonstrated by his incapacity for explicit learning.
CW has become synonymous for his moment to moment consciousness whereby the period of seconds is lost in a perceptual time void and where perceived information is lost as soon as his eyes close – quite literally in a blink – only to be confronted with the experience of a completely new ‘awakening’ repeated many times. CW’s semantic memory, though generally preserved in A.S., showed evidence of impairment as he is unable to produce object names, define words and comprehend written material, instead lending himself towards confabulation.
CW’s pattern of deficits in declarative memory can be explained by the neurological damage that he suffered. The major damage to the hippocampus (relatively destroying it) is the most likely cause of the severity of his amnesia, whereas the retrograde amnesia is attributed to the diencephalic damage, and semantic memory impairment adheres to the more widespread temporal lobe damage.
Functioning and Indications for Intervention
Contrary to CW’s deficit in declarative memory, his non declarative memory is left relatively unimpaired. There are many reports of CW’s implicit memory functioning, most notably his procedural memory for reading, playing, conducting and singing music which are practically preserved. Clive has, on more than one occasion, denied seeing a piece of music or even playing the piano, only to (when directed), sit down and play the piece and add “I remember this one”.
Additional evidence for CW’s implicit memory comes from the first few years of his condition where he began to abbreviate his questions, he would only need to ask his wife ‘How long?’ to be understood as to what was meant, ‘How long have I been ill?’ suggesting an awareness, on some level, that the question has been asked before, as well as the knowledge of the fact that she knows what it means.
Evidence for implicit learning comes from the report after eighteen months of his new home, where he has been taken for daily walks to feed the ducks, now asks ‘do the ducks want their tea?’ when prompted to put on his coat, ceasing to ask how long he has been ill – a seven-year obsessive habit.
Though his apparent disorientation, he has also gained other (purely) implicit memories like the layout of his residence where he is able to go to the bathroom, kitchen and dining room unsupervised. However, if he stops, gets distracted, or thinks en route he becomes lost. And though not able to describe his residence, his wife – Deborah – has reported how he will undo his seat belt and offer to get out and open the gate as they draw near. He is unable to explicitly identify the locations but is capable of action.
The role of music in CW’s implicit learning is certainly an interesting one, as not only is his procedural memory relatively unimpaired but he is also capable, providing someone puts the music before him to get him into action, of learning and practicing new pieces.
It is also reported that he also hummed something which he had not played for half an hour. This discovery is of great relevance to the following section on intervention as it suggests that this is could be down to rehearsal of it subvocally, perhaps reflecting use of the phonological loop process in memory encoding.
Broca’s area is a relatively contained section in the inferior frontal gyrus of the frontal lobe and is namely responsible for the production of speech and sounds. There is little evidence to suggest of a deficit in CW’s ability to produce speech and sound and therefore any relative damage to this area, which in turn enables the seeming subvocal rehearsal that has been reported. Seeing as CW appears to have some phonological functioning and fairly preserved implicit memory, this seems a rational starting point for rehabilitative intervention.
Proposed Intervention
Whereas in previous clinical approaches where rehabilitation was usually based on a broad range of therapies (CBT, psychotherapy, etc), neuropsychological therapy tackles small areas either to test theories or to increase the understanding of a particular subject area. In the case CW, it is the impairment experienced involving disorientation that will be the focal point of this intervention.
The intervention will operate at the level of impairment – the specific problem being disorientation. In terms of the intervention mechanism restoring or reinstating the original function – this seems very unlikely to be possible. The alternative therefore, is to instate an intervention mechanism that will utilise and develop existing capacities with the use of external aids and strategies to overcome the problem.
Implicit learning of routes through basic repetition would not be recommended in this case. Instead, it would be preferable to use the available existing/surviving capacities (i.e. subvocal rehearsal and procedural memory) – as this approach, if sufficiently effective, could be transferred for other possible applications in different situations.
CW’s procedural memory of music lends itself extremely neatly to the notion of journeys and routes due to its formulative and progressive nature. CW’s wife Deborah speaks of the “momentum of music” where it is said that music, much like any route – has steps, phrases, beginnings and ends (Wearing and Wilson, 1995).
In an article, author and neurologist Oliver Sacks (2007) provides a compelling narrative of this momentum indicating the link of memory and melody:
There is not a process of recalling, assembling, recategorizing, as when one attempts to reconstruct or remember an event or a scene from the past. We recall one tone at a time, and each tone entirely fills our consciousness yet simultaneously relates to the whole. It is similar when we walk or run or swim—we do so one step, one stroke at a time, yet each step or stroke is an integral part of the whole. Indeed, if we think of each note or step too consciously, we may lose the thread, the motor melody. (Sacks, 2007)
In normal automatisation of procedural information – which can range from making a cup of tea to driving a vehicle, the memory trace of each encounter is encoded and strengthened with each practise so that in future cases relevant information is retrieved quickly. In the case of CW this report suggests that a method of auditory mnemonic reduction encoding be used, set up with vanishing retrieval cues, gradually removed so as to encourage the strengthening of the mnemonic information in an errorless learning environment.
Encoding with visual and auditory mnemonics has been shown to be very effective in the development of creating links and encoding memorable retrieval cues (e.g. Burrows & Solomon, 1975; Sharps & Price, 1991; Haan et al., 2000) and provides a supported approach to the proposal intervention. The use of vanishing cues enables a ‘length’ of information to be divided into a number of relevant cues that are subsequently and gradually removed, thus resulting in a scope of learnt information which may require very few or even no recall cues. Errorless learning has been effective in a number memory-impairment cases (e.g. Tailby & Haslam, 2003; Page et al., 2006), where errorless learning employs a 100% correct response technique in strengthening memory traces.
Single Case Design Proposal
Neuropsychological intervention of any sort would usually naturally happen once the patient starts to demonstrate gaining a sense of normal functioning, that is – after the initial period of spontaneous recovering has occurred, as initiating intervention during this time of innate recovery is not suggestible – results may show absent or false improvement. In the case of CW however, this is not an area of concern.
The intervention will operate with auditory mnemonics and vanishing cues. It will be a tri-level multiple baseline design as to assess its effectiveness across and between situations. Three routes / journeys will be decided upon in relation to CW’s most important or habitual preferences. For the purpose of this proposal the three routes will be that from his room: (a) to the dining room (b) to the hall – the location of his piano and (c) outside via fire escape route.
The initial phase of the intervention will be reporting the baseline measurement for each route. This will be the amount of time it takes CW to get from his room to the each of the destinations, observations will also be made as of any experiences of disorientation and if so note down where along the route and how often they occur, using several measures maximise the stability of the assessment as they will be compared with the results of the intervention phase. The measurement phase will continue for 1 month before the first-level intervention is employed.
The second phase will start with the implementation of the first-level intervention – for the first situation (a). The route that CW takes will be marked off using posters showing a coloured symbol (e.g. a green triangle) at significant points. CW will also have accompanied with him a device that allows him to play a single relatively short melody, one that he is familiar with.
This will then be set to repeat, although it is assumed that one piece played from start to finish should last for more than sufficient time than it takes him to reach his destination – in this case the dinning room. During this time CW is encouraged to hum or sing the melody out loud. This first-level intervention for the first situation will continue for 2 months and measurements will be taken following the same concept as those in the baseline phase.
Following this will be the second-level intervention where the visual cues (green triangles) are gradually removed in suitable order so that there are no significantly unequal ‘gaps’ in cues along the route. CW will at this time still be encouraged to play and hum to the chosen melody along the route. This phase will be carried out over a total of 2 months, again, whilst measurements are taken.
The third-level intervention will entail CW not having access to the melody playing device, however he will still be encouraged to hum or sing what could be referred to at this point as the ‘dinning room melody’. Measurements will be carried out as previously done. This stage will continue for 1 month and then conclude the second phase of the intervention. After which the additional two routes will be initiated in sequence following the example of the first situation. A summarised list of the programme will look as follows.
Phase 1 – Multiple baseline recording
Measurements are taken across all situations (length: 1 month)
Phase 2 – Intervention of first situation (a) – to dinning room
Level 1 – melody played with cues (length: 2 months)
Level 2 – cues gradually removed (length: 2 months)
Level 3 – melody device removed (length: 1 month)
Phase 3 – Intervention of second situation (b) – to hall
Level 1 – melody played with cues (length: 2 months)
Level 2 – cues gradually removed (length: 2 months)
Level 3 – melody device removed (length: 1 month)
Phase 4 – Intervention of third situation (c) – fire escape route
Level 1 – melody played with cues (length: 2 months)
Level 2 – cues gradually removed (length: 2 months)
Level 3 – melody device removed (length: 1 month)
Phase 5 – Assessment of results
The appendix includes graphs that represent three possible outcomes of the intervention. The first in Appendix 1 demonstrates a successful intervention, evaluation of which will be discussed below. The second in Appendix 2 illustrates a clearly unsuccessful intervention whereas the third in Appendix 3 illustrates the possible results of a temporary positive effect of intervention followed by a decline in improved performance.
Signs that the intervention is successful will be a significant improvement in performance compare with baseline measurements. That is not necessarily to say that route-taking will be quicker, but that incidence of disorientation would have been significantly reduced.
The proposed evaluation of the intervention will consist of checking whether it has been successful in its aim and the reasons behind this outcome. If an improvement has been demonstrated it must be examined as to the source of change. Sources of change vary in terms of the circumstances of the case, for instance spontaneous recovery and innate brain recovery at this stage of the condition is highly unlikely and would have been captured in baseline measurements.
General treatment effects – i.e. what happens in CW’s home such as care and interactions are also another source of change which, in other cases may be an affect. The length of the intervention may allow changes in circumstance to affect performance. Major changes of this sort are unlikely however it would still be advisable to report any relevant changes. If an improvement has not been affirmed the intervention will be seen as not effective.
This doesn’t necessarily that the theoretical basis was at fault, the judgement of available case information may not have been sufficient. Problematic methodology could also be a cause. If the phases (and containing levels of aid) of the intervention were not carried out for long enough, or correctly the effectiveness of the proposed intervention would be compromised.
Providing the intervention was successful and improvement was made, it would be critical to examine the genuine extent to which the person’s life had changed for the better. This could take the form of improved functioning, increased independence and improved sense of well-being. It would also be relevant to examine the capacity to generalise the principle for application in other situations. The nature of the proposed multiple baseline design allows, on demonstration of positive results, that the intervention could be applied to similar situations and even for use in other cases of similar patients with A.S.
References
Aggleton, J. P., and Brown, M. W. (1999) Episodic memory, amnesia, and the hippocampal-anterior thalamic axis. Behavioral and Brain Sciences. 22 (4). pp. 425-440
Burrows, D. and Solomon, B. A. (1975). Parallel scanning of auditory and visual information. Memory and Cognition. 3 (4). pp. 416-420.
Haan, E. H. F., Appels, B., Aleman, A. and Postma, A. (2000). Inter-and intra-modal encoding of auditory and visual presentation of material: Effects on memory performance. The Psychological Record. 50 (3). pp. 577-86.
Page, M., Wilson, B. A, Shiel, A., Carter, G. and Norris, D. (2006) What is the locus of the errorless-learning advantage? Neuropsychologia. 44 (1). pp. 90-100
Sacks, O. (2007) The Abyss; A Neurologist’s Notebook. The New Yorker. New York. 83 (28). pp.100.
Sharps, M. J. and Price, J. L. (1991). Auditory imagery and free recall. The Journal of General Psychology. 119 (1). pp. 81-87.
Tailby. R. and Haslam C. (2003) An investigation of errorless learning in memory-impaired patients: improving the technique and clarifying theory. Neuropsychologia. 41 (9). pp. 1230-40.
Wilson, B.A. and Wearing, D. (1995) Prisoner of Consciousness: A state of just awakening following Herpes Simplex Encephalitis, In Campbell, R. & Conway, M. Broken Memories: Neuropsychological Case Studies. Oxford: Blackwell. pp. 15-30
