Discussion
cognitive impairment-, cognitive impairment, CERAD, MCI, dementia, generalised, cognitive decline
DISEASE
The aim of this study was to determine the effectiveness of a semantic-based memory-encoding strategy (SmeS experimental group) compared to cognitive stimulation (CS control group), for improving daily task performance, attention, memory and general cognitive function for older adults with mild cognitive impairment. The results indicated that the participants in the SmeS experimental group showed improved performance in the areas of daily task performance, memory and general cognitive function, whereas the CS control group did not produce any significant improvement after the intervention. A comparison of the two groups revealed that the SmeS experimental group had outperformed the CS control group in the CERAD Word List Recall and the Cognistat Similarity subtest. The results of this study have provided preliminary evidence of the semantic-based memory-encoding strategy intervention and support its effectiveness for people with mild cognitive impairment.The SmeS experimental group used chunking and the honeycomb method. When information is chunked together, memory span can increase significantly [The ability of the brain to learn and adapt has been successfully demonstrated for adults in later life with the use of memory training, even in small amounts [The results showed that the SmeS experimental group had significant improvement across a few areas. The responses to the DAD survey showed the participants’ improved daily function. Improvements in memory had also been shown by the CERAD-NAB J6 and Memory subtest of the Cognistat. Improvements in general cognitive function were shown by the Cognistat subtests of Attention and Similarity. These improvements are associated with the use of the semantic memory. The semantic memory relates new information to what is already known (information in the semantic memory). Deficits in working memory are evident in people with mild cognitive impairment. However, due to the use of already-formed memories (semantic information), the semantic-based memory-encoding strategy helps to associate from previous life contexts and enhance the encoding of information [Cognitive stimulation is a commonly used intervention that has been shown to benefit various cognitive domains in healthy individuals [Comparing the results of the two groups, the similarities and differences in scores are evident. Although the SmeS experimental group improved sigificantlly in the DAD of daily task performance, no significant difference was found in both daily task performance measures between the two group. This can be attributed to the use of daily tasks in the implementation of the interventions. Alternatively, this could have been due to the group’s already-high baseline score (SmeS experimental group baseline mean score = 4.95, CS control group baseline mean score = 4.37), where the performance had already reached the plateau and therefore further improvement would not be reflected by the assessment. However, there was a significant difference in improvement when the scores form the CERAD-NAB Word List Recall and the Cognistat Similiarity subtest were compared, with the SmeS experimental group showing greater improvement. These discrepancies between improvement in memory and general cognitive function may be explained by the use of the semantic-based memory-encoding strategy breaking down the information and forming associations to information that was already known.These results are important because they show great potential for the use of semantic-based memory-encoding strategy to be effective for people who have mild cognitive impairment. This study has added to the research evidence for the use of chunking and association as a semantic-based memory-encoding strategy to improve attention, memory, cognitive and daily task performance. When the strategy is used effectively, it could possibly delay the impact of cognitive decline on functional deterioration when the disease progresses, although further study would be required to verify this postulation. This study, combined with previous research, supports the benefits of intervening at the earliest possible stage of cognitive impairment [This study was limited by the small sample size and the non-randomisation methods. The selection criteria for people with MCI and the determination of other diagnoses through the report of the community centre staff posed a limitation on participants’ selection. The results are less likely to be able to be generalised to the greater population. Second, the intervention time of 10 weeks and lack of long-term follow-up might have reduced understanding of the participants’ long-term maintenance of these cognitive and functional abilities. Thirdly, the outcome measures being conducted before and after the intervention might pose a learning effect on participants and affect the results. The use of self-reported daily task performance measures could not provide objective measures of the participants’ daily task performances. The study result was also limited by the lack of follow-up assessment to evaluate if the cognitive gains sustained with the semantic encoding strategy have been preserved. Finally, a slight difference in the demographic characteristics such as education level in the two groups might create a possible difference in the results although no significance was found.Future research should focus on maintaining function over the long term and delaying the impact of cognitive decline due to mild cognitive impairment or dementia on daily functioning. In addition, future studies should have a larger sample size using a randomised method using objective, sensitive and mild cognitive impairment- or dementia-specific measures to allow for generalisability to the greater population. For example, a more sensitive word list test, such as California Verbal Learning Test, can be used to evaluate episodic functions [