Research Watch Report: Cognitive-Communication Intervention in Persons with Dementia

One of the best ways for busy clinicians to stay abreast of current research is by accessing systematic reviews and meta-analyses. Systematic reviews “involve a detailed and comprehensive plan and search strategy derived a priori, with the goal of reducing bias by identifying, appraising, and synthesizing all relevant studies on a particular topic” (p. 57, Uman, 2011). In other words, researchers develop a clinical question (e.g., Population - Intervention - Comparison - Outcome or PICO), then do an extensive search of available and relevant literature. Once the researchers identify the independent studies that are most appropriate for their clinical question, they summarize and synthesize the results of those studies to determine an answer to their question.

Systematic reviews may include meta-analyses. Meta-analysis is “a statistical technique for combining the findings from independent studies” (Crombie & Davies, 2009, p. 1). Meta-analyses go a step further than systematic reviews in that their purpose is to aggregate data from a number of relevant studies and include many participants to determine the treatment effects of a given intervention. The meta-analysis (of randomized controlled trials) is considered the highest level, or most rigorous type of research design, of the evidence hierarchy (see: https://www.asha.org/research/ebp/assessing-the-evidence/). 

Systematic reviews and meta-analyses are important for healthcare providers and provide a foundation for the development of guidelines to inform clinical practice (Moher et al., 2009). Indeed, ASHA’s National Center for Evidence-Based Practice in Communication Disorders (N-CEP) has developed a number of systematic reviews of various clinical populations to serve as a basis for clinical guidelines (see: https://www.asha.org/Research/EBP/EBSRs/). 

This research brief summarizes several systematic reviews/meta-analyses of cognitive-communication intervention in dementia. Articles 1 and 2 indicate that they followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist (Moher et al., 2009). This checklist includes 27 items that should be addressed in systematic reviews and meta-analyses. PRISMA also includes a four-stage flow diagram for identification of studies to be potentially included in the review, screening of the studies, determining their eligibility for inclusion, and finally, indicating the number of studies ultimately included in the review.

Maintaining a high level of quality is important because of the potential for systematic reviews and meta-analyses to influence clinical guidelines and practice patterns across a variety of disciplines. One protocol, the Downs and Black’s checklist (Downs & Black, 1998), which was used by the authors of Article 3, is a tool for evaluating the overall quality of the studies that are included in a systematic review/meta-analysis. Also, instead of PRISMA, the authors of Article 3 used the Cochrane Handbook for Systematic Reviews of Intervention (Higgins, 2008) to guide the reporting of the studies included in their article.

The topic for this research brief, cognitive-communication interventions among persons with dementia (PWD), is an important one for SLPs for several reasons. First, the number of individuals with dementia is on the rise. Currently, close to 6 million people in the United States are living with a diagnosis of dementia. That number is expected to grow to 14 million over the next four decades as our population lives longer (CDC, 2018). Worldwide, the prevalence is currently just under 36 million and is expected to approximately double every 20 years (Prince et al., 2013). Secondly, and related to the growing incidence of the disease, dementia places a heavy burden on families and caregivers. This burden often takes the form of financial worry, heightened anxiety, guilt, fatigue, and frustration, and leads to diminished quality of life for those involved (ASHA, 2019). Finally, speech-language pathology is the rehabilitation discipline most suited to assess and treat the cognitive-communication disorders associated with dementia. Treatment may include direct intervention with the PWD as well as indirect intervention in the form of family/caregiver training, to address a variety of issues such as maintaining cognitive-communication abilities for as long as possible, modifying the environment to decrease cognitive-communication barriers, and facilitating increased participation in activities of daily living.

Of further interest in this area of inquiry is the use of various terms and definitions of cognitive or cognitive-communication intervention. Special attention will be given to the terms and definitions provided for the different types of interventions included in these review articles in order to assist the reader in developing a clear understanding of similarities and differences across these articles.

Article 1: Folkerts, A., Roheger, M., Franklin, J., Middelstadt, J., and Kalbe, E. (2017). Cognitive interventions in patients with dementia living in long-term care facilities: Systematic review and meta-analysis. Archives of Gerontology and Geriatrics, 73, 204-221. 

Background: What was the rationale and/or clinical question guiding this study? The authors of this systematic review/meta-analysis cite a number of previous studies that investigated the effectiveness of various cognitive interventions on PWD. Some studies yielded positive results while others did not. The authors hypothesized that a possible reason for the inconsistencies was the heterogeneity of contexts from which the participants were recruited. Some participants were residents of long term care facilities, others were attending daycare centers, while still others were living at home. Because the level of care needed often changes as dementia progresses, comparing patients across these different settings may have inherently introduced a confound related to severity of the disease, hence, the varying results of previous intervention studies. Further, earlier investigations also varied in their use of control groups, which causes difficulty in interpreting results by introducing the possibility that something other than the experimental treatment/intervention was the reason for any changes. Specifically, the authors were interested in learning about different results based on whether the control group used was an active one or a passive one.

Active control groups are engaged in an intervention at the same time as the experimental group, but the control group intervention is not related to the experimental variables being measured, i.e., cognition. For instance, individuals in an active control group might participate in general recreational activities such as music or physical activity, while their peers in the experimental group are participating in a specific cognitive intervention. Passive control groups are not engaged in any type of intervention while the experimental group is involved in an intervention. The aim of this systematic review/meta-analysis was to: examine the effects of cognitive interventions among PWD living in long-term care, considering the studies’ experimental designs (e.g., use of active vs. passive control groups).

Method: How were the studies selected? The authors searched several databases for peer-reviewed articles that were designed as randomized controlled trials (RCTs), quasi-RCTs and controlled trials. Additionally, all studies selected for the systematic analysis/meta-analysis included only participants with a diagnosis of dementia (any severity level) living in long-term care, and whose treatment consisted of cognitive intervention. Studies that targeted caregivers (i.e., indirect interventions) were not included. A total of 27 studies were included in the systematic review, and 15 of those were appropriate for inclusion in the meta-analysis. The total number of participants across the studies in the systematic review was 491, and they ranged in mean age from 69.8 years to 87.8 years. Frequency and intensity of interventions varied widely among the studies. Some reported that intervention sessions took place once per week while others reported up to six sessions per week, and total hours of treatment ranged from 3 hours to 576 hours.

The authors identified five different types of cognitive interventions based on their prior knowledge of the literature: reminiscence therapy, cognitive training, cognitive rehabilitation, cognitive stimulation/reality orientation, and multi-modal interventions. Table 1 includes definitions of each of these types.

Table 1. Definitions of intervention types identified by Folkerts et al. (2017).

Results and Clinical Application: What does the synthesis of results suggest about the answer to the clinical question? The cognitive outcomes that were analyzed were: general cognition, memory, executive functions, motor processing speed, and visuoconstruction abilities. Other outcomes that were included in the analysis were quality of life (QoL), activities of daily living (ADLs), and depression/behavioral and psychological symptoms of dementia (BPSD).

Passive control groups. Results of the systematic review/meta-analysis revealed moderate improvements in general cognition in studies that used a passive control group (i.e., delayed treatment group). Cognitive training, specifically, yielded a large difference between the experimental group and the passive control group. Reminiscence therapy led to moderate gains for autobiographical memory, but it led to small gains for depression and QOL ratings, as did cognitive training and cognitive stimulation. When compared to the passive control group, those in the experimental group demonstrated large improvements in executive functions, while motor processing speed was moderately improved.

Active control groups. General cognition was moderately higher among participants who received reminiscence therapy, cognitive training, or cognitive stimulation, compared to an active control group. Likewise, reminiscence therapy had a moderate effect on depression scores. Outcomes for memory, executive functions, visuoconstruction, BPSD, QoL and ADLs did not appear to improve with cognitive intervention. In other words, the experimental groups did not show an advantage over the active control groups in those areas. Given that differences between experimental groups and their passive control group counterparts were larger than those found when comparing experimental groups to active control groups, this pattern might suggest that an intervention - regardless of whether it targets cognition specifically - might be helpful for general cognitive abilities and mood for PWD living in long-term care settings.

Article 2: Swan, K., Hopper, M., Wenke, R., Jackson, C., Till, T., and Conway, E. (2018). Speech-language pathologist interventions for communication in moderate-severe dementia: A systematic review. American Journal of Speech-Language Pathology, 27, 836-852.

Background: What was the rationale and/or clinical question guiding this study? The authors of this study site the increasing prevalence of dementia on a global scale, as well as diminished QoL and significant caregiver burden, as reasons for our need to know more about what types of cognitive-communication interventions may be most beneficial in this population. Specifically, they describe the presence of “responsive behaviors, including aggression, frustration, repeated questioning, and cursing” (p. 836) as a significant communication and QoL concern that is often magnified in later stages of the disease process.

Furthermore, the most recent survey data suggest that dementia makes up 15% of SLPs’ caseloads in healthcare settings, second to dysphagia at 39% (ASHA, 2017). Despite the growing need for research to guide evidence-based practice, the authors suggest that recent systematic reviews have not provided clear guidance regarding direct (face-to-face) and indirect (e.g., focusing on caregivers and/or environmental barriers) cognitive-communication interventions with PWD at more advanced stages. Therefore, the clinical questions guiding this review were focused on evaluating the evidence for these two different categories of cognitive-communication interventions and their effects on communication, participation (as related to communication), and overall well-being.

Method: How were the studies selected? The authors conducted a systematic literature search for relevant articles published between 1990 and June 19, 2017. In order to be included in this review, previous studies had to include participants who were diagnosed with moderate-severe dementia based on a standardized assessment such as the Mini-Mental State Examination (MMSE; Folstein, et al., 1975). The articles included also had to focus on direct or indirect cognitive-communication interventions with outcome measures related to communication, participation, and/or well-being. The authors excluded studies that reported outcomes from participants with comorbid diagnoses (e.g., prior CVA), as well as if interventions studied in an article could not be delivered by an SLP.

Ultimately, the authors identified a total of 11 studies that met criteria for the review. Ten of the studies investigated direct treatments. The studies, which were randomized controlled trials, non-randomized controlled trials, pre-test/post-test designs, and a case study, included a total of 352 participants with dementia, most of which were classified as Alzheimer’s or probable Alzheimer’s dementia. Participants ranged in age from 66 - 96 years. Treatment dosage and duration ranged from 1 hour to 45 hours total, and from 1 week to 16 weeks.

The authors identified three different types of direct cognitive-communication interventions examined in the extant literature: cognitive training, cognitive rehabilitation, and cognitive stimulation. Table 2 includes definitions of each of these types as well as specific examples provided by the authors in the review.

Table 2. Definitions of direct intervention types identified by Swan et al. (2018).

Results and Clinical Application: What does the synthesis of results suggest about the answer to the clinical question? The systematic review revealed that all 11 of the studies, comprising both direct and indirect treatments, found positive outcomes. Direct treatment approaches led to overall improvements in cognitive-communication functions. Specifically, direct cognitive stimulation groups and individual cognitive training approaches improved participants’ language skills based on measures such as formal language assessments. Direct interventions delivered in a group setting, including reminiscence therapy, led to increases on conversational participation measures including number of nonverbal communication acts and number of words used. Responsive (i.e., negative communicative) behaviors were decreased by a cognitive rehabilitation approach that focused on cueing for use of AAC. In addition, the authors reported that some of these positive outcomes associated with the use of AAC were maintained at a 30-month follow up assessment. The study that focused on indirect treatment through communication partner training resulted in improved conversational engagement on measures (e.g., increased number of words produced by the PWD per topic).

Ultimately, the results of this systematic review offer some evidence for the use of several different cognitive-communication intervention approaches, though the lack of research in this area prevents the authors from drawing conclusions about any one approach. This review suggests that group settings and the incorporation of supported group or individual conversation/discourse-level treatments are associated with improved functional communication and participation among individuals with moderate-severe dementia. Also noteworthy is that all of the studies included in the review were published between the years of 1992 and 2010, indicating a significant need for updated experimental research on the effectiveness of cognitive-communication interventions among individuals with moderate-severe dementia.

Article 3: Garcia-Casal, J., Loizeau, A., Csipke, E., Franco-Martin, M., Perea-Bartolome, M., & Orrell, M. (2017). Computer-based cognitive interventions for people living with dementia: A systematic literature review and meta-analysis. Aging & Mental Health, 21, 454-467.

Background: What was the rationale and/or clinical question guiding this study? These authors set out to explore whether computer-based cognitive interventions might provide cost-effective and functional improvements for PWD. They cite evidence from the English longitudinal study of aging (ELSA) which suggests that “computer-based leisure activity could be a protective factor against cognitive decline” (p. 454). They also cite other studies that have found behavioral interventions might offer a possible alternative to pharmacological interventions among PWD, and others that call for the need to improve upon existing non-pharmacological interventions for this population. The aim of this review was to examine the evidence for the effects of computer-based cognitive interventions on cognition, mood (anxiety and depression) and ADLs of PWD. In addition, computer-based interventions were compared to non-computer-based behavioral interventions to determine if an advantage exists for one over the other.

Method: How were the studies selected? The authors conducted a systematic review of the relevant literature. They included only peer-reviewed studies of PWD published between 2000 and 2014. The studies included were “before and after studies” (p. 456), randomized controlled trials, and case control designs. In addition, outcome measures for included studies had to be standardized, psychometrically validated assessments. These assessments included, for example, the Alzheimer’s Disease Assessment Scale - Cognitive (ADAS-COG; Rosen et al., 1984), the MMSE (Folstein et al., 1975), and the Modified Barthel Index (Mahoney & Barthel, 1965). Participants were to be PWD of age or severity level. Some of the studies included active control groups, while others included passive control groups. Some active control groups were involved in non-computer-based cognitive training activities while others were involved in other types of activities (i.e., physical activities).

The authors identified four different types of cognitive interventions: cognitive recreation, cognitive training, cognitive rehabilitation, and cognitive stimulation. Table 3 provides a description of each of these types.

Table 3. Descriptions of cognitive intervention types identified by Garcia-Casal et al. (2017).

Results and Clinical Application: What does the synthesis of results suggest about the answer to the clinical question? A total of 12 studies met the inclusion criteria, and a meta-analysis was carried out on those studies. Across the 12 studies, the analysis included a total of 700 participants, 376 of those having been identified as PWD. Treatment sessions lasted from 29 minutes to 210 minutes and were carried out over a range of 6 hours to 252 hours.

The meta-analysis revealed that, overall, computer-based interventions were effective for improving outcome measures among PWD for cognition and mood. In addition, the authors found that computer-based interventions had greater positive effects on cognition than did non-computer-based interventions. The analysis did not, however, find support for computer-based interventions over non-computer-based interventions for mood or ADLs. These results suggest that, for those PWD who are comfortable with using technology, computer-based cognitive tasks can be beneficial for improvement and/or maintenance of cognitive functions and mood.

Final Thoughts

Taken together, these three systematic reviews/meta-analyses provide evidence that direct and indirect cognitive interventions, both computer-based and non-computer-based, can help our clients with dementia and their caregivers. Specifically, following participation in cognitive interventions, PWD demonstrated improvements in a range of cognitive-communication areas including functional communication and participation. These types of interventions also increased mood, which is an important and often contributory factor in communication and participation.

Aside from the findings regarding the effectiveness of cognitive interventions, the authors of the studies highlighted the need for more high-quality research into specific types of interventions, as well as for more standardized terminology. For instance, all three reviews summarized here provided slightly different terms and descriptions/definitions of commonly referenced forms of cognitive interventions. These are provided for each systematic review/meta-analysis in Tables 1, 2, & 3. The descriptions/definitions of the types of interventions from all three articles summarized here are compared in Table 4 to illustrate similarities and differences. The comparison shows that several of the terms, cognitive training, cognitive rehabilitation, and cognitive stimulation, have similar descriptions across all three studies. However, studies parse these intervention types differently ^a, while others may not consider them as a separate category of intervention at all. For example, multimodal intervention was identified in only one study, as was the category of cognitive recreation.

Table 4. Descriptions/definitions of intervention types identified by all three systematic reviews/meta-analyses. 
^{a  Swan et al. (2018) considered both reminiscence therapy and reality orientation to be types of cognitive stimulation, whereas Folkerts et al. (2017) considered reality orientation to be almost significant enough to be a completely separate category. Folkerts et al. (2017) also considered reminiscence therapy as a separate intervention type.}

Ultimately, the evidence in the area of cognitive-communication intervention for PWD suggests that these individuals do benefit from direct and indirect skilled SLP services to enhance their communication, participation, and mood. Although we cannot definitively identify the most effective intervention types based on the current literature, we must continue to advocate for PWD and our profession so that these clients and their caregivers have an opportunity to receive our evidence-based services for meaningful cognitive-communication improvements.

References

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