A team of experts from fields including neurology and health communication were consulted to identify goals and research questions for this scoping review. Identified goals were to understand the empirical evidence base, identify research gaps, determine research opportunities, and provide a foundation for clinically focused communication guidelines. Specifically, the review addressed two research questions: (1) What is the scope and nature of published research on ALS and health communication about end of life? And (2) what, if any, recommendations are made in primary research articles whose central focus is end-of-life communication with patients living with ALS?

Scoping reviews are commonly undertaken when there is a broad question, a range of study designs, no prior knowledge synthesis on the topic, and an interest in identifying gaps and envisaging future research directions (45–48). The methodology used for this review was based on Arksey and O'Malley's five stages for scoping reviews: (i) identify the research question; (ii) develop the search strategy; (iii) apply inclusion and exclusion criteria to select articles; (iv) chart and collate the data; and (v) summarize and report the results (45). In accordance with recommendations for scoping reviews (47, 48), a quantitative, numerical summary analysis, followed by a qualitative thematic analysis of the subset of articles whose central focus was communication in the context of ALS and end of life was conducted. The discussion section completes the summary and reporting stage as it focuses on the meaning and implications of the study findings (47).

An expert health sciences librarian developed search strategies for the following electronic databases: MEDLINE (Ovid), EMBASE (Ovid), PsycINFO, CINAHL (EBSCO), SCOPUS, Dissertations and Theses Global (Proquest), and Web of Science, and EMB Reviews (Ovid) including Cochrane Database of Systematic Reviews, ACP Journal Club, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register, Health Technology Assessment, and NHS Economic Evaluation Database. The following legal databases were also searched: Westlaw, Heinonline and the Factiva subcategory “US law reviews and journals.” Search algorithms used controlled vocabulary within databases and synonyms for “amyotrophic lateral sclerosis,” “end of life,” and “health communication.” Date or other limits were not applied. Initial searches were completed in October 2015 and updated in January 2018. A second update was conducted in May 2021. At the time of the second update, all the EMB Reviews (Ovid) databases had been replaced by Cochrane Library (CDSR and Central Register of Controlled Trials). The search strategy used for Medline is included as a sample in Supplementary File 1; other detailed search strategies are available from the corresponding author.

Article records, including titles and abstracts, were retrieved and uploaded to bibliographic management software (Endnote 7). For the initial search and 2018 update, four coders removed duplicates and applied the inclusion/exclusion criteria to the article records that met the search criteria. Articles meeting the following criteria were included: (1) reported primary quantitative and/or qualitative empirical data; (2) addressed end of life for people with ALS; (3) discussed health communication; and, (4) were published in the English language. Health communication was defined as per the Medical Subject Headings (MeSH) thesaurus: the transfer of information from experts in the medical and public health fields to patients and the public, and the study or use of communication strategies to inform and influence health-related decisions (49). All coders received training and discrepancies were resolved through discussion to consensus during the training period. Coders then screened 10% of the article records and inter-coder reliability was determined by calculating the Light's kappa coefficient in Microsoft Excel as 0.87. Each coder independently screened one quarter of the remaining records. This same process was followed when assessing the full text articles. Based on 10% of the articles the Light's Kappa coefficient was calculated as 0.81. Two coders completed the 2021 update. The Kappa coefficient was calculated as 0.99 for screening the article records and coding the included full text articles.

Based on the research questions and expert input a web-based, standardized data extraction sheet was developed. Each selected article was coded for: bibliographic information, jurisdiction where the study was conducted, research design, study methods, participant population, sample size, quality of life and family burden, discussion of voluntary assisted death, and peripheral or primary focus on health communication. Three trained coders extracted data from the selected full text articles. The calculated Light's Kappa coefficient was 0.74. The Kappa coefficient for the 2021 update was 0.99. Numerical summary analysis was conducted based on the data extracted to a priori categories (47, 50).

Qualitative, inductive analysis was conducted on the subset of articles that were coded during quantitative analysis as having primary focus on health communication (the “communication subset”). Based on the research questions and expert input, key concepts and themes were identified using an iterative approach. Discussion to consensus was achieved by working through a small sample of articles. One coder coded the communication subset; the second coder coded 10% of the articles. Based on this 10%, the Kappa coefficient was assessed as 0.97 (initial and 2018 update) and 0.94 (2021 update) for the qualitative analysis. NVivo 10 software facilitated data organization and qualitative coding.

Literature searches returned 2,477 unique article records, of which 296 were potentially relevant and eligible for full-text review. Of these, 211 met the review's inclusion criteria for quantitative analysis. (See Supplementary File 2 for list of included studies). One hundred and ten articles focused explicitly on health communication. These comprised the ‘communication subset’ and were included in qualitative thematic analysis (Figure 1).

Eighty-one articles within the health communication subset (n = 110) highlighted the importance of discussions about end of life for people living with ALS. Twenty-eight articles noted the influence of communication on patient care, and 19 noted its influence on the therapeutic relationship between healthcare professionals and patients and/or their families. Fifty-five articles discussed communication about specific end-of-life options; 13 noted voluntary assisted death. Thirty-three articles included discussion of symptom management at end of life, for example, nutritional or respiratory support. Themes identified in the communication subset included communication quality (communication barriers and facilitators) (n = 81), difficult conversations (n = 72), and functional communication challenges (n = 45) (Table 5).

Articles that addressed the quality of communication between patients with ALS, families and healthcare professionals noted facilitators (n = 40) and barriers (n = 57). Facilitators and barriers were characterized not only by communication style, but also by information substance (what is communicated) and sufficiency (enough information to meet patient need). As might be anticipated, for example, ALS patients and their families valued open and/or “honest” communication with health care professionals (39, 51, 52, 106). In addition, researchers exploring the experiences of ALS caregivers noted that a lack of empathic communication “left the participants feeling shocked, bewildered, angry and devastated” (53). However, this current analysis found that a greater number of articles highlighted the importance of meeting the information needs of patients and families. For example, researchers investigating decisions about life-sustaining treatments reported, “the provision of full information was paramount, which in some cases included providing information in different formats” (54), and neurologists who provided needed or desired information were rated more highly by family caregivers (55). Further, a reviewed study found that ALS patients who “lack communication, information, and clear answers from health providers” experienced “frustration and despair due to a limited life time” (56). Seventeen articles noted seeking information outside the medical system, including online, from interpersonal sources and/or from patient advocacy organizations (18, 51, 54, 57–67, 118, 119, 148).

Of the 72 articles that addressed “difficult conversations,” 38 noted avoidance of end-of-life discussions by ALS patients, their families, and/or healthcare professionals. Twenty-four articles focused on communicating an ALS diagnosis. Articles drawing attention to functional communication challenges related to a motor speech disorder (n = 45) primarily highlighted the severity of communication impairments (n = 27) and strategies to address speech loss (n = 22) (Table 5).

This review identified a limited evidence base and lack of comprehensive recommendations for health communication about end of life with ALS patients. Despite increasing discussion and legalization of voluntary assisted death across jurisdictions (28–30) and its implications for ALS patients (30, 149, 150), there has been only a modest increase over time in empirical investigations of communication about end of life for this population. Moreover, most of the reviewed articles addressed end-of-life communication as a peripheral focus of investigation. In keeping with other studies, this review highlights the need for generic communication skills, including empathy and relationship building (151–154). Findings, however, bring attention to the importance of providing substantive and sufficient disease-related information, including information about symptom management and assistive devices, when discussing end-of-life issues. For people living with ALS, decisions about symptom management, for example dyspnea or dysphagia, may change the natural disease trajectory as technologies introduced for symptom management become life-support technologies (16). Recommendations for communication about end of life with ALS patients primarily target health professionals, providing only general suggestions for improving communication rather than specific, actionable guidelines similar to published guidelines for disclosing an ALS diagnosis (36, 38, 39). The following paragraphs discuss the scope of end-of-life, ALS-focused communication research, perceptions of communication quality, unique challenges for discussions of end of life with ALS patients, and a need for “actionable” communication recommendations that might guide effective communication in clinical practice.

The findings in this review highlight the multidisciplinary nature of health communication research and the concomitant challenge of finding a “home” for ALS-related communication research. Although advances with keyword searching and access to multiple databases mitigate some of these challenges, reviewed articles were published across a wide range of journals and were identified by heterogeneous and poorly standardized database subject headings (155–157). This may introduce challenges for clinicians seeking to find ALS-specific, evidence-based guidance for discussing end of life.

Quality of life for ALS patients and, to a lesser extent, family burden has been widely examined in the ALS literature. These themes appear prominently in the current review, with physical and psychological/emotional domains discussed most frequently as related to one another. For example, articles suggested that planning for end of life was influenced by fear of physical symptoms and of being a burden to loved ones (33, 158, 159). Although communication about the physical aspects of end of life may be viewed as a central task for healthcare professionals, findings suggest, unsurprisingly, that psychological/emotional, social, religious, and even financial factors may also be important aspects of end-of-life communication. In addition to the psychological and emotional toll on ALS patients and their families, research demonstrates substantial emotional burden for healthcare professionals caring for people with terminal neurological disease (41). While patient voices were well represented in the review, articles were less likely to examine the perspectives of healthcare professionals. Given the role that healthcare professionals play in discussing end of life with ALS patients, more research on healthcare professionals' perspectives is needed as a step toward developing guidance for end-of-life communication.

Voluntary assisted death, when discussed, was primarily contextualized within an overarching discussion of end-of-life options. Within the communication subset, very few articles noted assisted death. These findings may be an artifact of the lag between legislative changes and empirical investigation. They may also reflect a tendency toward symptom-driven communication rather than end-of-life discussions that are integrated into clinical care. For example, discussions about end of life may occur in tandem with decisions about initiating, continuing, and/or discontinuing life-sustaining interventions such as mechanical ventilation or enteral feeding tubes. Attitudes toward end-of-life options, including voluntary assisted death, vary across regions and cultures (28, 160, 161). With high mobility within populations, increasing attention to the influence of culture and personal beliefs on advance care planning and decisions for people with ALS (41, 118, 120, 162), and increasing access to voluntary assisted death in many jurisdictions (28, 29), the need for patient-centered evidence and communication guidance is increasingly important for sensitive, effective communication about palliative care and end-of-life options.

The integral role of communication for end-of-life care is documented in the palliative care literature (5, 163, 164). Yet, fewer than half of the selected articles focused explicitly on health communication. These articles—the communication subset—indicate that, despite the importance of online disease-related information (165–168) and support (169, 170) for ALS patients, healthcare professionals are critical information sources for patients and their families. This suggests an important role for professionals both in providing information about end of life, and helping people make sense of information from online sources. Although information needs have been identified as an important domain at the time of the ALS diagnosis (61, 165, 171), research is needed to identify and better understand the information that ALS patients and families want and need to make decisions that influence the disease course and end of life. For example, in contrast to cancer patients, life-sustaining interventions such as nutritional and respiratory support are considered “standard of care” for people living with ALS and are positively associated with improved quality of life (172, 173). Communication about accepting or forgoing such interventions is, therefore, particularly relevant to ALS (and, perhaps, other neurodegenerative disorders). It follows that information about the nuances and practicalities of palliative sedation for the withdrawal of such life-sustaining interventions is important for people with ALS and their families.

Many of the communication challenges identified by this review are not unique to people living with ALS. For example, both this review and the palliative care literature identifies healthcare professionals' reluctance to address prognosis and end-of-life discussion avoidance (41, 115, 174, 175); difficulties identifying appropriate times for conversations about end of life (5, 115, 164); and the changing needs of patients (163). ALS, however, presents additional communication challenges. First, findings demonstrate that disclosing an ALS diagnosis is closely associated with discussions about end of life. Second, throughout the disease course, clinicians must effectively communicate both the chronic and terminal facets of ALS (107). For example, clinicians must guide patients and families through iterative decisions about initiating, maintaining and potentially withdrawing life-sustaining support for nutritional and respiratory needs. Finally, this analysis highlighted functional communication challenges. Almost all ALS patients experience motor speech disorder with disease progression (176, 177). This presents a unique challenge for those seeking to facilitate full and ongoing patient participation in discussions and decisions about end of life.

Thematic analysis makes an important contribution to understanding of the recommendations emerging from the analyzed articles. A small number of themes with specific application were identified (for example, four articles recommended the use of decision aids). However, most recommendations were limited to the specific interventions or gaps in care identified in individual articles and lacked the systematized guidance that is required to operationalize findings for clinical practice. Thematic analysis, however, draws attention to three aspects of communication: processes, style, and the content of communicated information. Findings indicated a primary need for improved communication processes, for example, discussion of end-of-life issues both early and incrementally throughout the disease trajectory (52, 121). Providing substantive information that meets the needs of patients and families was equally important to communication style in the recommendations. These findings draw attention to a need for focused empirical investigation of concrete, evidence-based communication strategies, and the development clinical communication guidelines for discussions about end of life with people living with ALS.

The paucity of focused, end-of-life communication research and the lack of progress in the development of empirically-based communication guidelines for ALS may reflect the tendency for research funding to target marketable interventions and therapies (178, 179). Even among non-profit ALS Societies the overwhelming majority of research funding is directed toward laboratory research, pharmacological interventions, and devices (180–182). Topics such as health communication, which reside at the intersection of Medicine and the Social Sciences, tend to receive limited funding.

Empirically derived data about end-of-life discussions with ALS patients are primarily embedded in broadly focused investigations. Although there was a small increase in empirical articles, systematic investigation of communication about end of life is limited. The scarcity of research focused on communication, and the increasing number of empirical articles recommending more research in this area, may also reflect a need for proven research methodologies, as well as knowledge and expertise, that will address this evidence gap. Clinicians and researchers need to think of novel, patient-oriented methods to investigate both the communication practices of clinicians and the needs of ALS patients for information about end of life, both at the time of diagnosis and throughout the disease course. Investigations should yield specific, actionable recommendations for translation into policy and practice. This will provide a foundation for developing guidelines supporting end-of-life communication between health professionals and ALS patients and their families.

As discussed, findings may reflect policies and practices that direct research funding to marketable interventions and therapies. Despite the importance of these activities, communication is critical to the clinical management of ALS. Policies that promote the funding of communication research will provide a foundation for developing an evidence-base for compassionate, effective, and ethical communication about end of life, as well as evidence-based communication training in educational institutions and via continuing education for health professionals who care for ALS patients.

Finally, this review has implications for medical practitioners. The wide range of journals publishing research in this area of investigation may compromise access for practicing clinicians. Highly ranked journals that are specific to neurology and palliative care should seek to provide a home for this body for research that represents both the science and “art” of medicine. Further, this review draws attention to communication quality as mediated not only by core communication skills, but also by information substance and sufficiency. While emotional connection is important, the clinical expertise and information communicated by health professionals builds trust and “ownership” of care decisions (181, 182).

Clinical discussion of issues related to end of life has substantial impact on care and facilitates compliance with patients' wishes (169). Actionable recommendations and guidance are needed to support clinicians caring for patients with ALS. This is particularly important because ALS specialists and multidisciplinary ALS clinics are concentrated in large urban centers that may become inaccessible with disease progression. ALS patients frequently begin to rely on support from palliative and community physicians at a time when they need expert and nuanced information. Developing a strong empirical foundation and end-of-life communication guidance will support both specialists and non-specialists as they iteratively discuss life-sustaining therapies and end-of-life issues with ALS patients and their families.

This investigation followed standard methodological recommendations for scoping reviews, as well as Levac et al.'s recommendations to include both numerical summary analysis and qualitative content analytical techniques when summarizing and reporting results (45, 47, 48). Recommendations to consider the review's implications within the broader contexts of research, policy and practice were also followed (47).

A primary strength of this review is the focus on primary research articles. Although many review and commentary articles that may provide insight into end-of-life communication were excluded, this review makes an important contribution by documenting the paucity of empirical evidence in this area of investigation. Better understanding of the scope and nature of the evidence, both quantitative and qualitative, provides a starting point for systematically addressing evidence gaps. Further, because the review included all empirical articles available in the databases without time restriction, these data meet the study objectives and provide an overarching view of this research area.

There are limitations to this review. Critical appraisal of articles was limited to the application of inclusion/exclusion criteria. For example, articles that did not report primary quantitative and/or qualitative empirical data were excluded. The rigor of research processes within individual studies was not evaluated.Restriction to articles published in the English language presents another limitation. Communication, particularly about end of life, is rooted in cultural expectations and practice. Some of the review's outcomes could, therefore, be an artifact of the language restriction.

Finally, despite the profound impact of legislative changes on end-of-life decisions for ALS patients (68, 122, 150, 183), the heterogenous methods used in the fields of Medicine and Law presented a methodological limitation. Whereas empirical data are central to high quality evidence in scientific fields such as Neurology (184), legal research focuses on doctrinal and comparative analysis of authoritative texts with reasoning and conceptual analysis as an indicator of quality (116, 185). Therefore, articles published in legal journals did not meet study inclusion criteria. Although scoping review methodology facilitates review of articles with varying research designs (45), further methodological development is needed to facilitate review and analysis of high-quality evidence emerging from the disparate research traditions of Medicine and Law.