A call for globally responsive screening materials to account for heterogeneity in dementia syndromes

Abstract

Effective screening for communicative ability in dementia is vital to drive theoretical understanding and optimize care responsiveness globally. Communication is central to the human experience; however, routine clinical screening for progressive communication change remains limited due to a variety of resource constraints. Other challenges include the subtlety of early communication-led symptoms, heterogeneous underlying pathologies, and a lack of culturally diverse research and tools. To address the scarcity of dedicated assessment resources, future initiatives must maximize responsiveness to and representation of our global population to appropriately respond to the rising, and vastly diverse, dementia crisis.

Targeted screening for communication concerns is critical for later optimized clinical care. Targeted screening (1) expedites the suitability and responsiveness of care and (2) maximizes outcomes of intervention.^1,2 These benefits hold whether the outcomes are approached in a restitutive, compensatory, or palliative manner.^1,2 Communication is an imperative feature of the human experience and plays an indispensable role in patient autonomy, caregiver burden, health outcomes, and overall quality of life.^3–5 Unfortunately, despite its importance, our ability to screen for progressive changes to communicative ability in routine clinical settings remains limited, both in terms of resources and practice.^1,6,7 This is particularly problematic in scenarios where the onset of communication change is subtle, progressive in nature, and attributable to rarer conditions. ⁶ Primary progressive aphasia (PPA) is the hallmark clinical syndrome characterized by communication change that is notoriously difficult to detect at the mild stages.^8–10 This difficulty has been attributed to various issues, including but not limited to the subtlety and relatively low incidence of communication-led symptomatology,^9–11 heterogeneity in underlying pathology,^9,12,13 insufficient workforce preparation and support for this population,^11,14,15 and underspecified assessment materials.^6,16 The latter challenge is further exacerbated by the fact that most research on PPA and related clinical syndromes has been conducted in English-speaking Western countries.^10,17 As a result, findings, tools, and conclusions are restricted to small subsets of the global population. In fact, evidence by García et al. (2023) revealed disproportionate Anglocentrism in research on communicative ability in common dementia syndromes: while English speakers only represent 17% of the global population, more than two-thirds of research on this topic is based on this niche population. ¹⁷ Beyond the exact native language in question, studies of multilingual populations—and subsequent clinical guidelines and resources—remain even more scarce. ¹⁸

The true prevalence of communication concerns, and trajectory thereof, amongst people who are affected by neurodegenerative syndromes remains to be established. ¹⁹ Estimates suggest that a new diagnosis of dementia is formulated every three seconds worldwide, ²⁰ where Alzheimer's disease accounts for over half of these cases.^20–23 The vast collection of established dementia syndromes is notoriously distinguished by factors of behavior, etiology, and pathogenesis. Clinical assessment of dementia-related communication changes is often decontextualized, ²⁴ as in the widely-used Clinical Dementia Rating scale (CDR^®).^25,26 In particular, speech, language and communication all represent a complex interplay of many factors, but standardized documentation often reduces them to single constructs without additional nuance.^24,27 Whether communication change is led by degradation to these specific domains or cognition more broadly, ²⁷ accurate assessment is required to (1) make this judgement and (2) formulate appropriate plans of care. The existing heterogeneity in neurodegenerative syndromes can only be accounted for through the introduction of evidence-based screening tools that reliably differentiate profiles of cognitive-linguistic impact. Efficient screening materials that can be feasibly incorporated into routine clinical evaluation result in faster accurate diagnoses, earlier implementation of evidence-based care planning, and more immediate relief for patients, care partners, and families.^10,11,14,27

People, prior to or living with a diagnosis of dementia, may mention change in their communication. Amongst the most common concerns is generalized anomia (e.g., word-finding difficulties, expressed as “I can’t think of the name” or “That thing, you know”)—a core behavioral feature of many diagnoses with differentiated causes.^19,28–30 Change is inherently subjective and challenging to quantify without comprehensive evaluation. In the absence of comprehensive speech and language evaluation by domain experts in routine care (e.g., speech-language pathologists), easily implementable and evidence-based screening tools can help mitigate this issue. Speech-language pathologists are communication specialists who can then build upon the outcomes of screening measures to tease apart subtler elements of communicative ability and use these to shape intervention.^15,16,31,32 Screening leads to optimal clinical outcomes when concerning results are followed up by expert-led therapeutic intervention. However, people with cognitive or communication changes are rarely referred to speech and language intervention due to diagnostic challenges (exacerbated by a lack of tools) and limited awareness about the speech-language pathologist's role for these populations.^15,31,32

Present efforts to establish efficient and evidence-based resources across languages are instrumental to confront this gap in both theoretical understanding and clinical practice. A current example is the timely work of Fernández-Romero et al. (2024), ³³ where the investigators sought to establish the diagnostic efficacy of existing assessments of cognitive-linguistic performance (Addenbrook's Cognitive Examination [ACE-III] ³⁴ and Dépistage Cognitif de Québec [DCQ] ³⁵ ) or targeted towards communication (Mini-Linguistic State Examination [MLSE] ³⁶ ). In this work, 64 Spanish speakers completed Spanish adaptations of the three instruments to establish their diagnostic value for PPA. This work represents critical shifts away from Anglocentrism and towards a collaborative and international effort across languages, countries, and institutions, here represented by organizations in Argentina, Canada, and Spain. Similarly, work by Farina et al. (2022), ³⁷ documents methodological procedures to generate cross-cultural adaptations of dementia outcome measures for South African and Indonesian populations to promote responsible and representative comparisons between study populations and accurate data harmonization. Efforts such as these are fundamental to generate specialized, yet linguistically and culturally-appropriate resources to propel efforts to optimize current practices of diagnosis, symptom monitoring, and intervention. Needs will vary by study population,^38–40 but these differences should be established, validated, and not assumed. Future investigations therefore must provide educated interpretation of the generalizability of their methods and results, and even better yet, include the study of sociolinguistic, cross-cultural, educational, and socioeconomic variation. Recognition of these factors will be made possible by non-proprietary and collaborative multicenter investigations, led by a wealth of investigator perspectives, and with large and adequately representative research samples.^10,17,40

Globally responsive care to the rising crisis of dementia includes tools to systematically identify, monitor, and address progressive decline in communicative ability. Failure to recognize the role of communicative ability in neurodegenerative conditions and their differential impact across the spectrum of clinical syndromes, as well as insufficient cross-cultural adaptations, are prominent contributing factors to the existing scarcity of dedicated assessment resources for this population.