Case study VI
Studies suggested that even amnesic patients can acquire some types of new information through non-declarative memory (Baley et al., 2002; Cavaco et al., 2005), also acquire at least some new semantic information with less flexible way when extended training was provided (Baley et al., 2002;Stark et al., 2005; Stark et al., 2008). In addition, Miotto (2007) presented procedural learning techniques in the memory rehabilitation of amnesia following herpes simplex virus encephalitis (HSVE) case. A patient, L.M. who was a 44-year-old, was diagnosed with HSVE in 2004 damaged to the bilateral medial temporal and right basal frontal and insular regions. L.M. developed severe anterograde and retrograde amnesia even after he survived from infection. One year later after the onset of amnesia, L.M. started cognitive rehabilitation, he expressed his goals in rehabilitation as learn the names of the people who working with him and learn an efficient skill to learn new information and retention it especially from texts. Two studies (face-name training technique, retention of new information) were provided to achieve those two personal goals. For the face-name training study, two baseline designs (motor imagery strategy and visual imagery technique) were presented to exam which technique is more effective between a procedural learning and visual imagery learning. In motor imagery learning technique, the patient was encouraged to think about a gesture or motor movement that could be associated in person’s name and photograph, while in visual imagery technique, the patient was asked to draw a picture or letter to help him remember the name and photograph. L.M. significantly could remember more names under the motor movement condition than the visual imagery condition. For the retention of new information study, also two baseline conditions (the PQRST technique, the Rehearsal technique) were compared on the immediate and the delayed recall. L.M.’s correct responses for the PQRST were higher than those for the rehearsal on both the immediate and the delayed recall condition. Results showed that the motor movement technique to learn names of people lead significantly better performance of L.M. than a visual imagery condition, also the PQRST method improve LM.’s verbal retention and recall capacity. It was possibly explained by L.M.’s less impaired left temporal region. This study demonstrated some improvement through a combination method of memory rehabilitation techniques that were based on implicit memory system in amnesic patients.

Discussion
Due to various causes produce propound amnesia, the symptom and processing of amnesia are variable for individuals. For this reason, it is unable to apply same rehabilitation interventions to every amnesic patient. Rehabilitation for amnesic individuals should be considered in each unique condition of patients. Even though individualized rehabilitation plan cannot always achieve positive outcome in most case of amnesia, in literature, it is possible to see that certain types of amnesic patients retain abilities to learn new information.

Memory loss is the most important issue in amnesia, reviewed studies above suggested that amnesic patients especially who restrictively damage to medial temporal lobe (MTB) structures or basal forebrain nuclei have higher chance to learn and retain new information through their perceptual motor skills or non-declarative memory system. All patients with amnesia in case studies above demonstrated their abilities to learn some new information and successfully retain it. How those available to them?

In Baylet et al. (2002) study, E.P. demonstrated considerable learning of new factual information most his learning depended on non-declarative memory. Authors assumed about it as several ways, E.P. has less intact of the parahippocampal cortex within the medical temporal lobe and this region might support him to learn some amount of declarative information, or some declarative information might be acquired independently of the MTB, or E.P.’s non-declarative memory might be supported by some other brain system.
In case of T.E. (Stark et al., 2005), he was apparently able to learn new semantic information at a more conceptual level than E.P. However, his learning was clearly slower than a control group and learning did not accessible to conscious awareness due to MTL damage. Stark et al. suggested that their presented errorless learning technique might do the function instead of what MTL normally doing to help integrate information into the neocortex thus T.E. can acquire semantic knowledge gradually over many times of training.

The case of M.H. was damaged to basal forebrain region by rupture of aneurysm located in the ACoA. M.P. was able to learn and retain new cognitive and perceptual motor skills associated with an adequate use of external aids. This case suggested that anterograde amnesia following basal forebrain damage is able to improve memory performance when enough external cueing is provided, also can learn separate modal stimuli even unable to learn the proper relationships and integrations skills of those stimuli
What unique condition of A’s case was (Duff et al., 2008), she has minimal MTL damage even her severe memory impairment. Not only well developed external interventions but also her less intact limbic system and frontal lobe possibly help her keep developing self-awareness, plans for the future, and successfully managing social and emotional outcome.
The patient L.M. with profound amnesia following HSVE also showed his ability of learning people’s name with based on a motor imagery strategy and new verbal information with memory improvement technique. It assumed that his relatively less impaired left temporal region and more restricted damage to the medial temporal lobe might serve his some declarative memory capacity.

When damage to the medial temporal lobe that includes the hippocampus, amygdale, the parahippocampal gyrus, entorhinal and perirhinal cortices, it will commonly produce impairment of explicit or declarative memory capacity of individuals. These memories refer to the long term memory system thus deficit of these abilities mean one’s difficulties in encoding, storing and retrieving information from the past event or learning new information. Above case studies suggested that if individuals restrictively damage to MTL structures, they possibly acquire some new semantic information or procedural skills with extensive training and external aids. The learning would be depending on their procedural memory or non-declarative memory system. Even inflexibility of learning and necessary of extended training time, memory rehabilitation for those amnesic patients will be a great help to improve their independence and better quality of life.

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