Abstract

A working group of the 2016 International Summit on Intellectual Disability and Dementia was charged to examine the terminology used to define and report on dementia in publications related to intellectual disability (ID). A review of related publications showed mixed uses of terms associated with dementia or causative diseases. As with dementia research in the non-ID population, language related to dementia in the ID field often lacks precision and could lead to a misunderstanding of the condition(s) under discussion, an increasingly crucial issue given the increased global attention dementia is receiving in that field. Most articles related to ID and dementia reporting clinical or medical research generally provide a structured definition of dementia or related terms; social care articles tend toward term use without definition. Toward terminology standardization within studies/reports on dementia and ID, the Summit recommended that a consistent approach is taken that ensures (a) growing familiarity with dementia-related diagnostic, condition-specific, and social care terms (as identified in the working group's report); (b) creating a guidance document on accurately defining and presenting information about individuals or groups referenced; and (c) using definitions and data, such as subjects' ages, sex, level of ID, residential situation, basis for dementia diagnosis, presence of Down syndrome (or other risk conditions), years from diagnosis, and if available, scores on objective measures of changing function, in reports on neuropathologies or cognitive decline or impairment.

Language can and does shape and form our perceptions of a condition or situation. As noted by Alzheimer's Europe (2013, p. 11),

Some words and metaphors are used liberally and paint a very biased picture of dementia, whilst others are avoided and considered demeaning, depersonalizing, and insulting. Even standard medical terms are sometimes used with great caution due to an awareness of the possible impact on people's lives and wellbeing. Words clearly matter. They describe, communicate and reinforce our current perceptions of dementia.

Nomenclature (or terminology) is a system of names or terms, or the rules for forming these terms, in a discipline or field of study. Reviews of publications (i.e., journal articles, book chapters, reports, documents, and plans) involving intellectual disability (ID) show varied uses of terms associated with dementia or the diseases or conditions causing it (Janicki et al., 2016). Terms in use (including dementia, Alzheimer's, and other similar descriptors) often lack precision or consistency and may be used loosely and applied inappropriately. As with publications in the mainstream dementia field, this misuse may be attributed to a lack of understanding of the distinction in the terms, the nuances involved with neuropathologies, language usage preferences and translational difficulties, or inconsistent use of language, as well as absence of or inconsistency in an agreed upon core group of methods used in diagnosis. Notably, language related to dementia in the ID field often lacks precision in relation to its peculiarities from onset to progression and often leads to a misunderstanding or incomplete representation of the condition(s) under discussion.

A lack of precision in general applications, as witnessed by recent efforts in the mainstream Alzheimer's and dementia field to address the same issue, appears common. This concern over coherency regarding terminology was discussed by Taylor (2016) at the Alzheimer's Disease-Related Dementias 2016 Summit, held in the United States under the auspice of the National Institutes of Health (Foundation for the National Institutes of Health, 2016). Taylor listed a range of terms that are in use in the field and stimulated a dialogue on dementia-related nomenclature regardless of the etiology, specific clinical syndromes, or underlying etiologies. She noted a number of problems stemming from inconsistency in terminology, such as Alzheimer's disease being used synonymously with dementia, low public awareness of other forms of dementia, and a lack of recognition that Alzheimer's disease services are also applicable for those persons affected by non-Alzheimer's-based dementias.

The problems stemming from inconsistent terminology were also addressed at a meeting of the U.S. National Advisory Council on Alzheimer's Research, Care, and Services, which under the National Alzheimer's Project Act (NAPA) is responsible for the U.S. National Plan to Address Alzheimer's Disease (Department of Health and Human Services, 2012). Among the issues raised was the rationale for the adoption of updated clinical terminology within the most recent Diagnostic and Statistical Manual of Mental Disorders (DSM-5; APA, 2013), and the range of terms in use for various dementias, leading to a desire to introduce terminological coherency in planning documents (Petersen, 2016).

The updated clinical terminology refers to the DSM-5′s replacement of the terms mild cognitive impairment and dementia with minor neurocognitive disorder and major neurocognitive disorder, recognizing distinctions between distinct or progressive stages. The APA's DSM-5 changes were designed to recognize a spectrum perspective and varying incidence of locus of decline related to different etiologies, and provide more clinical and diagnostic precision in identifying variations in the presentation of dementia, particularly when dementia was attributed to causes other than Alzheimer's disease and presenting without the classic symptoms inherent in Alzheimer's (Simpson, 2014). It also was an attempt to remove some of the stigma associated with the word dementia. Within the new terminology, the focus is on decline rather than deficit in function and the term expands the categories to include other etiological conditions (e.g., HIV and acquired brain injuries), which do not necessarily occur in association with aging. Concerns about standardization of language have been increased by this change, as the new terms have clinical utility but not general societal usage, and have not yet generally been adopted by the major Alzheimer's or other dementia-related organizations internationally in public education and fund-raising campaigns. Introducing the term neurocognitive is also potentially confusing when ID also has aspects of neurocognitive dysfunction, and support for the use of the word disorder is questioned in the ID field as it sees the term as stigmatizing (Wehmeyer, 2013). Another consideration is that although the new DSM-5 is in use in some Western countries, the use of the definitions and diagnostic coding found in the ICD-10 (World Health Organization [WHO], 1992) is more prevalent worldwide, leading to some disparities in what terms clinicians and authors may use in medical and research reports, respectively.

Consequently, the National Advisory Council inserted a recommendation into the 2016 U.S. National Plan Update that stated that “Emphasis should be given to the standardization of terminology in dealing with cognitive and dementing disorders” (p. 55). Further, to address this issue head-on, the 2016 Update recommended that “an integrated conference should be convened to develop consistent language for cognitive disorders among scientists, care providers and the public… [and there is a need to] engage all of the stakeholders around these issues to reach a consensus for the benefit of persons with dementia, their family members and caregivers, and the scientific and service communities” (Assistant Secretary for Planning and Evaluation [ASPE], 2016; p. 55).

Conveyance of the Notion of Dementia

Language usage and terminology is germane to how people affected by dementia are viewed to the extent that terms used minimize stigma (Garand, Lingler, Conner, & Dew, 2010). Clearly, “people-first” language (e.g., adults with dementia) creates more positive imagery and can go far to minimize negative perceptions. Language uses such as “adults with dementia” are preferable to terms such as “demented,” victim,” and “sufferer,” which tend to be pejorative and maximize stigmatization (Dementia Engagement & Empowerment Project [DEEP], 2015). Such positive terms also focus on the individuals rather than the condition.

Communicating the definition and process of dementia to people with ID creates a further conundrum. To enable understanding, language and phrasing need to be at a word-level that organizations communicating with the general public, caregivers, advocates, or adults affected by dementia, can effectively use to convey the concepts associated with dementia. Further, the concepts need to be communicated in a manner so as to explain the essence and implications, and convey the seriousness of the condition while not creating confusion or undue anxiety. Siberski (2012) has addressed the concern of how the general public integrates clinical conceptualizations and reacts to information about diagnoses.

An aspect of communicating is the ease with which the general population grasps the concept behind a clinical disease or neuropathology—so avoiding “high science language” in documents directed toward general readership audiences can facilitate understanding. Using terms and definitions that are in common usage can help to ensure the communication of messages. Conversely, creating definitions that minimize the impact of the course and eventuality of brain changes leading to dementia can leave conditions untreated (Siberski, 2012). To examine the success of concept conveyance to the general public through the level of language used, the Summit working group analyzed both the reading ease and grade level of definitions conveyed by different dementia, health, and disability organizations when defining dementia (see Janicki et al., 2016 for the full report listing the terms and definitions). Of the 16 definitions extracted from major dementia-related organization websites and documents, the reading ease level ranged from 60.70 to 0.0 (X = 26.68) and the grade level ranged from 7.8 to 18.6 (X = 13.84). (In general, the higher the reading ease score, the more generally understandable wording is; with respect to the grade level, lower scores correspond with lower grade level reading abilities.) It appears that most of the definitions were expressed using complex concepts, even when directed at the general public. For those directed toward professionals, despite clarity that dementia is not a disease itself but a group of behavioral and/or function symptoms that can accompany certain diseases or conditions, the definitions used were more in the realm of technical language.

Language and terms are a further challenge for ID organizations, as they have to convey both information about the condition and forewarn caregivers of the condition's severity and eventual impact. How wording is constructed depends on the audience and message to be conveyed, and often the explanations lean toward complexity. This is true even among Down syndrome advocacy organizations, where the definitions and explanations of dementia (and Alzheimer's disease) used to inform their constituents tend toward complexity (see Table 1). However, when materials are developed specifically for people with ID, concepts have been explained in a simpler manner. As an example of a plain language definition of dementia, the Down's Syndrome Scotland's (n.d.) publication for adults with ID, states “Dementia is an illness in the brain. It affects many things, but mostly the way people remember and do things” (p. 3).

Table 1

Statements Related to Dementia/Alzheimer's Disease by Major English-Language Down Syndrome Organizations

Statements Related to Dementia/Alzheimer's Disease by Major English-Language Down Syndrome Organizations
Statements Related to Dementia/Alzheimer's Disease by Major English-Language Down Syndrome Organizations

Although it was not the function of this Summit statement to offer a standardized definition of dementia, it was recognized that the condition's primary features are characterized by the progressive loss of brain function that occurs with certain neuropathological diseases or trauma, often associated, but not necessarily related, to aging (others have addressed this characterization in depth; see Chertkow, Feldman, Jacova, & Massoud, 2013; Small et al., 1997). Such neuropathologies include, among others, Alzheimer's disease, Parkinson's disease, Pick's disease, and cerebrovascular accidents. The neuropathologies vary and have differing effects, but all have in common the eventual expression of progressive behavioral and cognitive changes and decline generally defined as dementia. This expression, in most instances, includes (a) eventual marked memory disorders and impaired reasoning; (b) personality and behavioral changes; and (c) loss of self-care, mobility, and communication. The principal aspects of the expression are related to the type of dementia (i.e., based on the etiology). However, it is recognized that features that may initially be taken for dementia-like behavioral dysfunctions may instead be the result of adverse drug reactions, depression, psychological trauma, or a range of other causes—with their defining feature a clearing or reduction of symptoms upon correct diagnosis and appropriate intervention (Desai & Grossberg, 2001).

Further, it was not the intent of this Summit statement to rectify inconsistencies in dementia-associated language usage across the general field of dementia (see Janicki et al., 2016, for examples of the variations), but to promote the understanding of the distinctions among the terms in prevalent usage and advance the application of precise usage and agreement on dementia-related terms that are commonly used in association with ID. Such a result would advance clearer differentiation and appropriate usage of clinical terms such as dementia; Alzheimer's disease; cognitive impairment; Alzheimer's disease spectrum; preclinical Alzheimer's disease; dementia due to Alzheimer's disease; mild cognitive impairment due to Alzheimer's disease; early versus late onset disease; mild, moderate, and advanced dementia (Alzheimer's disease); and others. We are not proposing a standard definition of dementia or acceptance of a range of associated terms that would be applied in work in ID—no such consensus on term usage exists in the general dementia literature or policy documents (save for those noted earlier in the DSM-5 [APA, 2013] or ICD-10 [WHO, 1992] for diagnostic purposes). We are, however, suggesting that workers/researchers/educators do provide an operational definition of dementia of their choosing so as to offer readers a clear understanding of the variables and notions related to the population being described.

Applications of Terms

How terms are used can affect clarity in understanding which population is being referenced and what conditions are being discussed. In a sampling of available articles and reports related to ID and dementia undertaken by the Summit's working group, term-usage was found to be variable and at times less than clear (see Janicki et al., 2016). Authors in general used dementia as a common term defining the nature of the condition, however there was often mixed reference to Alzheimer's disease, dementia of the Alzheimer's type, and generic dementia, without linkage to standard definitions (such as those in the DSM-5 and ICD-10). There was also an absence of defining whether the dementia being reported was progressive. Although the usage served the intended purpose—of defining the general concern of the article—it left open interpretations of (a) how the condition was identified, (b) to what degree it was progressing (or if progression was a concern), and (c) what may have been the underlying neuropathology. Some of these data may not always be readily available in social care research, but should be available in medical-/health-related research and in articles advancing or relying upon standardized assessments.

Defining the sample under study also has import and implications for research related to dementia in the ID field. The Summit working group's study also noted the high preponderance of articles in the ID and dementia literature that focused predominantly on Down syndrome (Janicki et al., 2016). Given the high risk for Alzheimer's disease among adults with Down syndrome this is not unexpected. However, it is important that authors are clear when reporting results and generalizing effects that the information provided relates to dementia in adults with Down syndrome (if this was the population), as there are undoubtedly differential patterns of onset, effect, and mortality in the greater population of adults with ID who do not have Down syndrome. Often in articles and reports, the number or percentage of participants with Down syndrome (and their sex and ages) is not identified within the sample; this may confound generalizability unto the greater population of adults with ID, and misinform on the epidemiology of dementia. Also, as most studies involving adults with Down syndrome relate to dementia of the Alzheimer's type, this also should be noted in the subject descriptions, and/or any variations in forms of dementia should be noted. Such detail will also highlight the number of study participants where an accurate diagnosis has not been made and the type of dementia is not known.

As what is popularly considered chronological aging can span 30 or more years, dementia-oriented studies should consider grouping data into age categories that reflect the younger-older and older-older grouping of subjects. Given that early-onset dementia is prevalent in adults with Down syndrome, the age span for younger-older may begin in the 40s and the older-older with age 60. When adults absent Down syndrome are the focus of studies then younger-older may begin in the 60s, and later age groupings may include those aged 75 and older—similar to general population reports. Such groupings can help establish patterns in incidence, related features (such as co-morbidities), and staging. Also, when reporting subject recruitment, methodology sections in reports should contain explicit definitions of dementia and at what dementia stage recruitment occurred. Although, identifying stage of dementia can be confounded by the degree and nature of the ID, efforts should still be made to define it as accurately as possible (Krinsky-McHale & Silverman, 2013). When reporting staging, terminology should reflect the spectrum of cognitive impairment when that is known in the study subjects.

The Summit working group observed that most articles related to ID and dementia were using prevalent dementia-related terms, rather than the DSM-5 terminology (e.g., neurocognitive disorders); this is also observed in the general dementia literature. Also, that the articles reporting assessment and clinical or medical research were more apt to provide a definition of dementia or related terms, whereas social care articles tended to only use the term itself and not define it or provide substantiation of study subject diagnoses. The working group suggested that it would increase research and practice utility if social care articles also provided definitions and the basis for ascribing dementia to the persons in the studies, thus offering more precision and permitting cross-article comparisons and contrasts. Further, as many of the articles examined failed to define the sample with respect to age, sex, level of ID, etiology, and other demographic variables, the standardization of reporting subject information recommended here would also increase utility. Also, judicious use of common terms among key words in manuscript submissions will aid in locating relevant articles following publication (e.g., Alzheimer's disease, cognitive impairment, dementia, Down syndrome, neurocognitive disorders, neuropathology, ID, etc.)

Commentary

The intent of this Summit statement is to reflect discussion at the international meeting in Scotland to promote the understanding of the distinctions among terms in prevalent use with respect to ID and dementia, and to advance usage that more accurately reflects the concepts cited, and agreement on commonly used dementia and intellectual disability-related terms. Terminology needs precision to accurately convey the conditions and services being discussed. The Summit proposes that authors, irrespective of the focus of the article, provide (a) operational definitions of conditions being considered, (b) ancillary demographic and clinical data, (c) study sample parameters, particularly the numbers (and percentages) of subjects with Down syndrome, and (d) information about how diagnoses were obtained, as well as the protocols and instruments employed. In social care articles, authors should offer a definition or explanation of the program(s) or service(s) under discussion. Readers would then be offered a clearer understanding of the population being described and the features being studied, and thus replication in future studies and comparisons across existing studies would be facilitated.

Recommendations

The Summit goals were to address issues associated with nomenclature (or terminology), seek agreement on a common taxonomy related to cognitive impairment and dementia among persons with ID and encourage use of standardized terminology within studies and reports on dementia and ID. With this in mind, the Summit recommends:

  • To promote positive imagery, organizations, researchers, educators, and workers adopt and use image enhancing language when describing persons with intellectual disability affected by dementia and avoid language that stigmatizes or dehumanizes;

  • To promote standardized understanding of the meaning of terms used to describe services and conditions related to dementia and intellectual disability, that a taxonomy be adopted for general use. A taxonomy of unvetted terms related to defining dementia and dementia services prevalent in dementia and intellectual disability publications is found in the appendix of the full Summit report (see Janicki et al., 2016) and can offer user guidance on the development of a formal taxonomy;

  • To help with reporting and describing events or conditions related to intellectual disability and dementia, that a guidance document be created on accurately defining and presenting information about individuals or the group being referenced to include both formal diagnostic criteria and general definitions of various dementias. We recommend that the guidance document be supported by a consortium of associated intellectual disability, gerontology, and dementia groups, and appear in a relevant publication (for archival purposes); and

  • To standardize reporting of subjects and outcomes from studies, researchers, educators and workers follow recommendations for harmonizing data in reports addressing neuropathologies, behavioral and functional changes, and cognitive decline or impairment. Such reports should use recommended definitions and at a minimum include the subjects' ages, sex, level of intellectual disability, residential situation, co-morbidities, basis for dementia diagnosis, presence of Down syndrome (or other risk condition), years from diagnosis, and if available, scores on an objective measure of changing function from a recognized and validated dementia scale.

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Author notes

The authors are the primary members of the Summit working group on nomenclature. This consensus statement was developed as an output from the 2016 International Summit on Intellectual Disability and Dementia, held in Glasgow, Scotland, 13-14 October 2016, and hosted by the University of Stirling and University of the West of Scotland, funded by the RS MacDonald Trust, the Scottish Government, and Alzheimer Scotland. Collaborating sponsors included the National Task Group on Intellectual Disabilities and Dementia Practices (NTG) in the United States and the University of Illinois at Chicago. The Summit was composed of individuals and representatives of many international and national organizations with a stake in issues related to adults with intellectual disability affected by dementia. The contents of this statement were partially developed under a grant from the United States Department of Health and Human Services, Administration for Community Living (ACL), National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR) Grant # 90RT5020-03-00. However, those contents do not necessarily represent the policy of the U.S. Department of Health and Human Services, nor the endorsement by the U.S. federal government. The opinions expressed represent those of the Summit participants and of the NTG.