A Computer-Assisted Errorless Learning-Based Memory Training Programme for Patients with Early Dementia

Corresponding Author:

David WK Man
Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Yuk Choi Road, Hung Hum, Hong Kong
Tel: (852) 2766-6711
Fax: (852) 2330-8656

Abstract

Background

Memory training can be effective in enhancing the cognitive function of older adults with cognitive impairment and may delay the onset of dementia.

Objective

The aims of this study were to develop a theory-driven, computer-assisted errorless learning (EL) memory programme (CELP) for patients with early dementia, and to compare the training outcomes of a CELP group with those of a therapist-led errorless learning training programme (TELP) group and a control group (CG).

Methods

A randomized control trial (RCT) with a single-blind research design was adopted. The Clinical Dementia Rating Scale (CDR) screened older participants with early dementia and their performances were evaluated before and after the intervention and during 3-month followup by the Mini-Mental State Examination (MMSE), the Dementia Rating Scale (DRS), Hong Kong List Learning Test (HKLLT), brief Assessment of Prospective Memory-Short Form (BAPM) for carers and Geriatric Depression Scale.

Results

Seventy-five participants were successfully recruited into the CELP group (n=30), TELP group (n=22) and CG (n=23) and completed the study. Participants showed statistically significant improvements in post-test scores for the DRS total score and its memory sub-score, with greater improvement in the CELP group than the TELP group and CG. Significant positive changes in the HKLLT immediate recall sub score, the MMSE and the BAPM were also found in the CELP group.

Conclusion

Computer-assisted EL can be an effective strategy to enhance the memory function of those with early dementia. Their encoding problems, working memory, executive function and prospective memory function can be improved by a CELP intervention. Having regular cognitive training or a home programme might maintain their cognitive functions.

Keywords

Early dementia, Memory training, Errorless learning, Computerised

Introduction

Dementia is a neurodegenerative disease, a progressive impairment of cognitive functions occurring in clear consciousness (in the absence of delirium). Global impairment of intellect is the main feature, with deterioration in multiple cognitive domains manifested as difficulty with memory, attention, thinking, and comprehension that is severe enough to affect a person’s daily living function [1,2]. Memory impairment can be the major presenting symptom of dementia and impairment of episodic memory and semantic memory in dementia has been reported [3]. One of the specific memory problems found in early dementia can be prospective memory (PM) failure [4]. Both time- and eventbased PM are correlated with retrospective memory and executive functions [5] and they are important predictors of independence in day-to-day functions [6]. Memory training can be effective in persons with mild to moderate dementia [7-9]. An evidence-based review of a special training technique, known as the errorless learning (EL) training programme, showed that it could improve memory function in dementia patients [10]. EL is a better learning method compared with the trial-and-error methods used for memory deficit [11] this is because it can compensate for neurocognitive deficits as they relate to the acquisition of new skills and abilities in rehabilitation [12]. The training principles are namely: the learned task is broken into components; over-learning of components is achieved through repetition and practice; training progresses from simple to complex in a hierarchical manner; immediate positive feedback is given to reinforce learning and a nonthreatening approach is adopted, using hints; vanishing cues and spaced retrieval strategies are incorporated. [13-15]. Also, computer-assisted cognitive interventions can be very effective when applied together with a comprehensive training programme in persons with dementia [16,17]. Computerised cognitive training (CCT) programmes have led to positive neuroimaging outcomes in older adults [18] and CCT has been applied to dementia and questionable dementia, demonstrating positive training results for memory function [19-21]. As it is important to ensure active participation to maximise training effects, some EL programmes have been integrated with computerised rehabilitation [13,18,22,23].

Thus, the purposes of this study were to develop and implement a computerised EL-based memory-training programme for patients with early dementia, and to compare the training outcomes of this programme with a therapist-led EL-based programme and a waiting list control group.

Methods

▪ Participants

The selection criteria included: aged 60 years old or above, both genders, at an early stage of dementia as screened by The Clinical Dementia Rating Scale (CDR) with a score of 1, mentally stable (as reflected by a Geriatric Depression Scale score ≤ 8), able to follow instructions and with an attention span of 30 to 45 min. The exclusion criteria were participants with severe visual or hearing impairment, computer phobic, and having impaired physical functions that inhibited the use of a touch-screen computer.

▪ Procedures

Ethical approval was sought from the Ethical Committee of the Hong Kong Polytechnic University and Clinical Research Ethics Committee of the Kowloon West Cluster in the Hong Kong Hospital Authority. Written consent was obtained from the participants and their caregivers before assessment and training. Participants were then allocated randomly to the following treatment groups: a computerassisted errorless learning program, a therapistled training programme and a waiting-list control group. Independent, blinded assessors performed outcome evaluation of participants at pre- and post-test, and at 3-month followup. Most of the participants completed all the outcome evaluations, including the follow-up testing. The intervention was led by occupational therapists with prior specialist training in using errorless memory programmes. The training programmes were implemented on an individual basis, around twice a week, with twelve 30- min training sessions, which were completed in around 6 weeks. The computerised EL memorytraining programme was run by using a touchscreen notebook computer with a touch-pen input device. Therapists provided guidance if the participants had difficulty using the computer input device or had literacy problems. Similarly, the therapist-led errorless learning programme was run on an individual basis. A training manual containing colour-print images was used. Therapists implementing the training were provided with the same set of instructions and gave similar immediate positive feedback to participants, as did the computer-assisted training programme. The waiting-list control group received cognitively challenging activities such as card sorting, perceptual and memory games of equal duration to the activities in the experimental groups.

▪ Instrumentation

Screening tool: The Clinical Dementia Rating Scale (CDR) [24] was used to screen suitable participants in the present study. The CDR is a widely adopted global assessment instrument used to indicate the staging of dementia severity. It is a semi-structured interview with patient and caregiver [25]. A CDR score of 1 indicates that a person is in the stage of mild dementia. Participants with a CDR score of 1 after assessment by the Chinese version of CDR were recruited. The Geriatric Depression Scaleshort form (GDS) [26,27] was used to identify if participants had mood problems. A score of 8 or below (out of 15) indicates a low possibility of depression.

Outcome measures: The outcome measures listed here were used for pre-test, post-test and 3-month follow-up evaluation.

1. Mini mental state examination (MMSE): In this study, a validated Chinese version of the MMSE was used, which assessed orientation, memory, visual-spatial copying and language abilities. This is a well-known cognitive screening tool in the elderly [28]. The scores range from 0 to 30, where higher scores indicate better cognitive function. With reference to the education of the older adults, different cut-off scores are used for dementia: a score of 22 or below for those with more than 2 years of education, a score of 20 or below for those with 1 to 2 years of education and a score of 18 or below for those with no education. The reported sensitivity was 97.5% and specificity was 97.3%. The reported testretest reliability was 0.78 and the inter-rater reliability was 0.99.

2. Mattis dementia rating scale (MDRS): The Chinese version of the Mattis Dementia Rating Scale (DRS) was adopted in this study [29]. The DRS consists of five subscales: attention, initiation/preservation, construction, conceptualisation and memory. A total score of 144 with a cut-off score of 112 was used to differentiate persons with dementia. The cut-off scores versus full scores for the sub-scales are: attention 29/37; initiation/perseverance 26/37; construction 3/6; conceptualisation 28/39; and memory 18/25. The sensitivity and specificity of the scores were 80.0% and 91.6%, respectively. The Cronbach’s α was 0.89.

3. Hong Kong list learning test (HKLLT): This consists of two 16-word lists in which all of the words are two-character nouns. The words are from four categories and are organised randomly. The test consists of three immediate recall trials, and two delayed recall trials (10 min and 30 min). In this study, the HKLLT- Form A with random conditions was used [30].

4. Brief assessment of prospective memoryshort form (BAPM) for carers: This self-report prospective memory evaluation was used, with 16 questions covering aspects of basic self-care and IADL. Each question was scored from 1 to 5, where a lower score indicates better functioning for elderly participants [31,32].

Intervention: EL-based memory training programmes: Two memory-training programmes were developed based on cognitive reserve and neuroplasticity theories of dementia, which suggest that the brain’s neuroplasticity reserve can be enriched through cognitive experience provided through training [33,34]. The programmes also incorporated EL, used together with spaced retrieval and vanishing cues [35,36] designed into a computer-assisted programme (CELP) or therapist-led programme (TELP). The content and structure of both programmes were similar, except for the delivery mode. They were designed using a culturally relevant training programme with familiar daily-life training content and gradation of training was based on the level of functioning, habits and interests of Chinese older adults. The basic training principles included the following: a) the learned task was broken into components; b) over-learning of components was achieved through repetition and practice to enhance mastery; c) training progressed from simple to complex (two answers upgraded to three answers); d) immediate positive feedback was provided to reinforce learning; e) a nonthreatening training atmosphere was provided, with hints; f) vanishing cues and spaced retrieval strategies were incorporated. The rationale for adopting a specific EL programme was to bypass errors and strengthen accurate associations, as Alzheimer’s disease patients have difficulty in self-correcting errors. The level of difficulty of questions was set appropriate to the level of cognitive function of the participants. For the 12 training sessions, the training scenarios adopted related to everyday life tasks (Table 1). The programme was structured with training components including: basic training on various memory types such as sensory memory (visual and auditory), working memory and prospective memory; memory strategies for using mnemonics (like chunking, organisation and categorisation) and learning principles, and also name/face association; advanced memory training on the application of strategies to daily life activities including home making, habit training, money management, shopping and community living skills. Immediate positive feedback was integrated into the training to encourage active participation of the participants (Table 1). Atypical training session had three parts: 1) attention, 2) working memory, and 3) focus on one training theme relating to memory (dual task, prospective memory, name/face recognition/memory strategies, habit training, or shopping or community living tasks, in order of complexity).

Table 1: Outline of Errorless Learning (EL)-based memory training programme.

Results

One hundred and fifteen participants were recruited and 75 (26 male and 49 female), ranging from 68 to 91 years old, with mean age of 78 years (SD=5.0). Thirty participants were randomly assigned to a computer-assisted memory-training group (CELP), 22 to a therapist-led training group (TELP) and 23 to a waiting-list control group (CG) respectively. The demographics, baseline comparisons of mental state (MMSE), cognitive functions (DRS, HKLLT, BAPM-carer) and mood status (GDS) were comparable among the three groups (Table 2).

Table 2: Demographic characteristics of subjects and baseline outcome measures of CELP, TELP, CG.

Table 3 summarises the cognitive function and mood state among the three groups, at three intervals (pre-test, post-test and three-month follow-up). An ANOVA with repeated measures showed that there was a significant interaction effect of group x time for all cognitive functions, except BAPM and emotional outcomes (GDS). Sub-group analyses were performed for these outcomes at each time point to control for the effect of time (Table 4).

Table 3: Comparison of group effect and time effect of CELP, TELP and CG.

Table 4: Comparison of pre- and post-test and 3-month follow up for CELP, TELP, CG.

▪ MMSE

Table 3 indicates a significant interaction effect for group x time on MMSE-time: F (2,72)=3.52, p=0.01, effect size=0.09). There was a significant group (treatment) effect for mean MMSE scores: F (2,72)=4.43, p<0.01, effect size=0.11. There was a significant effect of time for mean MMSE scores: F (2,72)=19.62, p<0.001, effect size=0.98. Table 4 shows that there were statistically significant between-group differences in MMSE post-test scores (p<0.001) and MMSE 3-month follow up scores (p=0.03) among the three groups. Tukey HSD tests showed that the CELP group performed better than the CG during the post-test (p=0.01).

▪ DRS scores

Similar to MMSE, there was a significant time x treatment effect for DRS total, F (2,72)=5.34, p<0.001, effect size=0.12, a significant group (i.e. treatment) effect: F (2,72)=3.60, p=0.03, effect size=0.09, and a significant time effect: F (2,72)=10.16, p<0.001, effect size=0.12. A one-way ANOVA, followed by a post-hoc test, revealed a statistically significant difference among CELP, TELP and CG (p<0.001) in the post-test (Table 4). Table 3 shows the time x group (treatment) interaction effect in DRS subscale scores (concept, memory). Table 4 shows that the memory subscale score was significantly higher in the post-test (p=0.027) and 3-month follow up (p=0.002). Post-hoc test showed that the CELP group had improved more than the TELP group and the CG (p <0.01) at the two time points. For DRS concept scores, the only significant difference was found in the post-test situation. Post-hoc test shows that the CELP group improved more than the CG (p<0.01) and no significant difference was found between the CELP and TELP groups.

▪ HKLLT

Though HKLLT (total, immediate recall) time x group (treatment) interaction effects were found (Table 3), only immediate recall demonstrated a time effect in the post-test (p=0.05) among the three groups (Table 4). The post-hoc test showed a greater improvement in the CELP group than in the TELP group and CG (p<0.01).

▪ BAPM-carer score

There was a significant difference among the mean BAPM scores taken at pre-test, post-test and 3 month follow-up: F (2,72)=7.6, p<0.001, with a small effect size of 0.131. However, the time x group interaction effect was not statistically significant. During 3-month follow up, greater improvement was found in the CELP group than in the CG (p<0.05), but there was no difference between the TELP group and the CG.

Discussion

Positive training effects were found for errorless training programmes that were implemented in computer-assisted or therapist-led modes. Early stage Alzheimer’s disease patients seemed able to use EL training strategies well, with a better encoding of information and reinforcement of the retrieval of information through memory strategies reinforced in the training programme [37,38]. Improvement in the CELP group was greatest in regard to cognitive functions (MMSE, DRS and HKLLT). Computer-assisted errorless training programmes have the advantage that there is more audio-visual feedback from the computer programme to reinforce the learning of memory strategies. Participants in the CELP group might have enhanced their sense of achievement and they were proud of showing others that they could operate the computer, even though they were new users. Participants were also found to be highly motivated to attend the full training programme as scheduled.

There were pros and cons to using computerassisted training modes for early Alzheimer’s disease patients. The computer-assisted programme was a more standardised programme, with very interactive visual and auditory elements that reinforced errorless learning. Graduation of the programme could be built in. For example, to increase the difficulty of the training, a longer delay time could be given for delayed recall. Also, more regular stimulating positive feedback could be integrated into the training programme. This would save the therapists’ time and provide quality individualised memory training programmes to dementia patients. However, some early Alzheimer’s disease patients might need more individual guidance and support to attend a structured memory-training programme.

This study showed initial positive results for a CELP intervention in early Alzheimer’s disease patients. More innovative and creative cognitive training programmes might be developed later for healthy older adults or clients with mild cognitive impairment to enhance their brain health and reduce the risk of older adults developing dementia. Due to limitations in the intensity/period of the training programme and the small sample size, some intervention outcomes did not achieve statistical significance. We suggest increasing the number of training session from 12 to 15 sessions, with some sessions lengthened gradually from around 30 to 45 min while participants gradually build up their attention span.

Our findings show that errorless learning, repetition, an active-learning mode with familiar daily life content, interactive programmes and computer-based programmes are effective memory-training strategies for early Alzheimer’s disease patients. However, because we did not compare the EL programme to a non-EL programme, it is uncertain whether an EL memory strategy is more effective Alzheimer’s patients. Further research is therefore needed to examine this.

The computer-assisted EL has been proposed as an effective strategy for memory enhancement in persons with early AD. Whether this kind of strategy is applicable to other non-AD neurodegenerative diseases such as Parkinson’s disease should be explored further. As the computer-assisted EL training targeting at encoding process or reversing neurodegenerative change within the hippocampus and the extended neuronal network such as the medial temporal or parietal lobe may share similar neuro-regenerating effect in AD or non-AD type of memory impairment [39].

To date, other dementia can be attributed to cerebral, hormonal or metabolic changes and demand interventions. For instance, in persons with diabetes mellitus, insulin resistance in the brain can lead to dementia. Insulin resistance has been proposed to be relevant in adopting similar hypothesis of AD pathogenesis through the Damage Signals hypothesis [40]. The present study of dementia associated neurodegenerative disease may be partly relevant to the insulin resistance in the brain due to a similar damage on the brain parts though due to different pathophysiology. Moreover, the current study did not address level of severity of dementia associated neurodegenerative disease (early AD) and CELP training outcomes. It is worthwhile to extend the findings of this study to another important study in comparing the relationship between the types (for example, AD, diabetes) with severity (mid, moderate and severe in AD or comparable severity using insulin resistance in brain) in using the same training strategy for positive outcomes.

Conclusion

We found positive cognitive changes among patients in the early stages of Alzheimer’s disease after attending an EL memory training programme. A clearer, more comprehensive conclusion might be found in future when a larger, multi-centre, randomised control trial is conducted, comparing EL and non-EL training and using computer-assisted and/or therapistadministered modes.

Acknowledgements

The authors are grateful to Mr. YC Ip and staff members of Occupational Therapy Department and the Psychogeriatric Team of Kwai Chung Hospital, the participants and their care-givers who took part in or supported this study.

Disclosure

The authors report no conflicts of interest in this work.

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