Association of Young-Onset Dementia with Pre-Existing Peripheral Vestibular Disorders

Abstract

Background:

The relationship between young-onset dementia and peripheral vestibular disorders remained largely unknown although this association was observed in the older population.

Objective:

This case-control study aims to investigate the association of young-onset dementia with a pre-existing diagnosis of peripheral vestibular disorders using a population-based data from Taiwan’s Longitudinal Health Insurance Database 2010.

Methods:

This study included 989 patients with young-onset dementia and 2967 propensity-score-matching controls. Differences in baseline characteristic between patients with young-onset dementia and controls were investigated using chi-square tests or t-tests. Multiple logistic regression models were employed to assess the association of young-onset dementia (outcome) with pre-existing peripheral vestibular disorders (predictor).

Results:

Compared to patients without young-onset dementia, those affected by this condition exhibited a statistically significantly higher rate of peripheral vestibular disorders (18.3% versus 8.2%, p < 0.001). Furthermore, our analysis found notable between-group disparities in the rates of Meniere’s Disease (3.5% versus 2.0%, p= 0.015), benign paroxysmal positional vertigo (2.4% versus 1.1%, p= 0.006), and vestibular neuritis (2.4% versus 1.1%, p= 0.003). Multiple logistic regression analysis showed that the presence of prior peripheral vestibular disorders increased the odds of young-onset dementia [2.603 (95% CI = 2.105∼3.220)] after adjusting for age, sex, monthly income, geographic location, urbanization level, hyperlipidemia, diabetes, coronary heart disease, hearing loss, and hypertension.

Conclusions:

The study findings demonstrate a notable association between young-onset dementia and pre-existing peripheral vestibular disorders, suggesting that vestibular malfunction could play a role in the development of young-onset dementia.

Keywords

Alzheimer’s disease dementia peripheral vestibular disorders young-onset dementia

INTRODUCTION

Dementia, a syndrome characterized by a decline in memory, thinking, behavior, and the ability to perform everyday activities, is traditionally associated with advanced age. However, dementia that manifests before the age of 65, known as young-onset dementia, is often overlooked and poses a unique set of challenges within neurology and geriatrics. A systematic review and meta-analysis indicated that the overall global age-standardized prevalence of young-onset dementia was 119.0 per 100 000 population in the age range of 30 to 64 years. 1 This type of dementia has a heterogeneous etiology, encompassing a range of neurodegenerative, vascular, and other pathologies. 2 Recent research has begun to explore the association between young-onset dementia and peripheral vestibular disorders, a group of conditions affecting the vestibular system of the inner ear, which is crucial for maintaining balance and spatial orientation.

Peripheral vestibular disorders, including Meniere’s disease, benign paroxysmal positional vertigo, and vestibular neuritis, are primarily known for causing vertigo, dizziness, and balance issues. 3 The vestibular system’s role in spatial orientation and navigation suggests a potential link between vestibular dysfunction and cognitive impairments, as spatial disorientation may serve as an early indicator of dementia. 4 Several cohort studies have demonstrated an elevated risk of dementia in patients with benign paroxysmal positional vertigo. 5 This association is further supported by a large-scale study of Korean older adults aged 60 or above. 6 While this association was observed in the older population, the relationship between young-onset dementia and peripheral vestibular disorders remained largely unknown.

The current study aimed to investigate the association of young-onset dementia with prior diagnoses of peripheral vestibular disorders using a case-control approach, leveraging data from Taiwan’s Longitudinal Health Insurance Database 2010 (LHID2010).

MATERIALS AND METHODS

Database

The case-control study retrieved its sample from Taiwan’s LHID2010, which contains the medical claims and registration files of 2,000,000 beneficiaries under the National Health Insurance (NHI) program. The NHI program provides universal coverage to all Taiwanese citizens since its implementation in 1995. The LHID2010 sample, randomly drawn from the year 2010 Registry of NHI beneficiaries, is representative of the population in terms of gender, age, and average payroll-related insurance deductions according to reports by the National Health Research Institutes of Taiwan. Many epidemiological and clinical care researchers from Taiwan have utilized deidentified data derived from this database for their studies. 6

The research was granted approval by the Research Ethics Committee of National Taiwan University (202012EM075) and adheres to the Declaration of Helsinki. Due to our utilization of deidentified administrative data furnished by the LHID administration, obtaining informed consent was deemed unnecessary.

Identification of study patients

We identified all patients between the ages of 30 and 64 who received a first-time diagnosis of young-onset dementia (as indicated by ICD-9-CM codes 290.0, 290.11, 290.12, 290.13, 290.20, 290.21, 290.3, or 294.1; ICD-10-CM codes F02.80, F02.81, F01.50, F01.51, F03.90, F03.91 and G30) during an ambulatory care visit from January 2011 through December 2019. We designated the date of the initial diagnosis as the index date and refined our inclusion criteria to only include patients with a minimum of two separate claims indicating a diagnosis of young-onset dementia (n = 3,059). This approach minimized potential misclassifications arising from diagnostic coding errors. We also excluded 2070 individuals with histories of major psychosis or substance-related disorders (indicated by ICD-9-CM codes ranging from 291to 299 or 303 to 305 and ICD-10-CM codes ranging from F10 to F19), stroke, or traumatic brain injury prior to their index dates. As a result, the final analysis sample consisted of 989 patients with young-onset dementia.

To investigate the correlation between peripheral vestibular disorders and young-onset dementia, we employed a propensity-score-matching technique to select controls from the remaining individuals aged 30–64 years in the LHID2010’s Registry of beneficiaries. Those with a history of dementia noted in their medical claim were excluded. Propensity scores for all selected 989 patients with young-onset dementia and remaining beneficiaries were calculated using logistic regression models that took into account sex, monthly income, geographic location, age, urbanization level of residence (ranging from most to least urbanized), coronary heart disease, hypertension, diabetes, hyperlipidemia and hearing loss (ICD-9-CM code 389 or ICD-10-CM codes H90 or H91). Finally, using a nearest neighbor random matching algorithm employing caliper adjustment set at +/–0.02 as an a priori value for calipers calibration; sampled patients with young-onset dementia were matched one-to-three with controls without young-onset dementia. For cases, the year of index date was assigned as when they received their first diagnosis of young-onset dementia. For controls, it was simply a matched year wherein they had an ambulatory care visit. As such, the study sample comprised of 989 cases affected by young-onset dementia and 2967 controls without this condition.

Exposure assessment

We identified instances of peripheral vestibular disorders by ICD diagnosis codes, including Meniere’s disease (ICD-9-CM 386.0 or ICD-10-CM H81.0), benign paroxysmal positional vertigo (ICD-9 386.11 or ICD-10 code H81.10), vestibular neuritis (ICD-9 386.12 or ICD-10 H81.2), and the other unspecified vestibular disorders including peripheral vertigo, unspecified: ICD-9 386.10, other peripheral vertigo: 386.19, unspecified vertiginous syndromes and labyrinthine disorders: 386.9, Aural vertigo: ICD-10 H81.31, other peripheral vertigo: H81.39, unspecified disorder of vestibular function: H81.9, and other diseases of inner ear: H83. Participants with a peripheral vestibular disorder diagnosed before the index date of their young-onset dementia diagnosis were categorized as having a pre-existing condition of peripheral vestibular disorders.

Statistical analysis

Statistical analyses were conducted using the SAS System for Windows, version 9.4 (SAS Institute, Cary, NC). Chi-square tests and t-tests compared baseline characteristics between cases with young onset dementia and controls. Multiple logistic regression models assessed the association of young-onset dementia with pre-existing peripheral vestibular disorders after accounting for sex, monthly income, geographic location, age, and urbanization level of the patient’s residence, diabetes status, hypertension prevalence rate, hyperlipidemia occurrence rate, and hearing loss status. Estimated odds ratios (ORs) and corresponding 95% confidence intervals (CIs) measured variations in the odds of pre-existing peripheral vestibular disorders between cases with young-onset dementia and controls. All p-values reported are two-tailed; a p-value< 0.05 was considered statistically significant.

RESULTS

Table 1 summarizes sociodemographic characteristics of cases with young-onset dementia and controls. After propensity-scored matching, we found that there were no statistically significant differences in age (p = 0.971), sex (p > 0.999), monthly income (p = 0.956), geographic location (p = 0.986), and residential urbanization level (p = 0.997) between patients with versus without young-onset dementia. In addition, the prevalence of hyperlipidemia (p > 0.999), diabetes (p > 0.999), coronary heart disease (p > 0.999), hearing loss (p > 0.999) and hypertension (p > 0.999) did not differ between groups.

Table 1

Demographic characteristics and medical co-morbidities of the study sample (n = 3,956)

Variable	Cases with young-onset dementia (n = 989)		Controls (n = 2,967)		P
	Total no.	%	Total no.	%
Age, mean (SD)	60.7 (7.1)		60.7 (7.1)		0.971
Males	370	37.4	1110	37.4	> 0.999
Monthly Income					0.956
< NT$1∼15,841	255	25.8	752	25.4
NT$15,841∼25,000	377	38.1	1,132	38.1
≥NT$25,001	357	36.1	1,083	36.5
Geographic region					0.986
Northern	520	52.6	1,558	52.5
Central	204	20.6	627	21.1
Southern	251	25.4	741	25.0
Eastern	14	1.4	41	1.4
Urbanization level					0.997
1 (most urbanized)	302	30.5	913	30.8
2	267	27.0	795	26.8
3	146	14.8	426	14.4
4	136	13.7	418	14.1
5 (least urbanized)	138	14.0	415	14.0
Hypertension	563	56.9	1,689	56.9	> 0.999
Coronary heart disease	279	28.2	837	28.2	> 0.999
Diabetes	403	40.8	1,209	40.8	> 0.999
Hearing loss	95	9.6	285	9.6	> 0.999
Hyperlipidemia	576	58.2	1,728	58.2	> 0.999

As shown in Table 2, the prevalence of peripheral vestibular disorders was statistically higher in those with young-onset dementia, compared to controls (18.3% versus 8.2%, p < 0.001). Similarly, significant between-group differences were observed upon examining each type of peripheral vestibular disorders: Meniere’s disease (3.5% versus 2.0%, p= 0.015), benign paroxysmal positional vertigo (2.4% versus 1.1%, p= 0.006), vestibular neuritis (2.4% versus 1.0%, p= 0.003), and the other unspecified vestibular disorders (12.2% versus 4.4%, p < 0.001).

Table 2

Prevalence of pre-existing peripheral vascular disorders (PVD) among cases with young-onset dementia versus controls

Variable	Total
	Cases with young-onset dementia (n = 989)	Controls (n = 2,967)	p
	N, %
Cases with PVD	181 (18.3)	243 (8.2)	< 0.001
Cases with Meniere’s disease	29 (3.5)	56 (2.0)	0.015
Cases with benign paroxysmal positional vertigo	20 (2.4)	31 (1.1)	0.006
Cases with vestibular neuritis	20 (2.4)	29 (1.0)	0.003
Cases with *other PVD	112 (12.2)	127 (4.4)	< 0.001

PVD = peripheral vestibular disorders, *other unspecified vestibular disorders including Peripheral vertigo, unspecified: ICD-9 386.10, Other peripheral vertigo: 386.19, Unspecified vertiginous syndromes and labyrinthine disorders: 386.9, Aural vertigo: ICD-10 H81.31, Other peripheral vertitgo: H81.39, Unspecified disorder of vestibular function: H81.9, and other diseases of inner ear: H83).

Table 3 presents the crude and covariate-adjusted odds ratios (ORs) for young-onset dementia in the multiple logistic regression models. The presence of pre-existing peripheral vestibular disorders increased the odds of young-onset dementia by 2.603 times (95% CI = 2.105∼3.220), after adjusting for age, sex, monthly income, geographic location, urbanization level, hyperlipidemia, diabetes, coronary heart disease, hearing loss, and hypertension. Meniere’s disease (adjusted OR = 2.603; 95% CI = 2.105∼3.220), benign paroxysmal positional vertigo (adjusted OR = 1.801; 95% CI = 1.136∼2.858), vestibular neuritis (adjusted OR = 2.201; 95% CI = 1.245∼3.891), and the other unspecified vestibular disorders (adjusted OR = 3.099; 95% CI = 2.365∼4.061) were each associated with an increased likelihood of young-onset dementia.

Table 3

Crude and covariate-adjusted odds ratios for young-onset dementia

Variable	Presence of young-onset dementia
	OR (95% CI)	Adjusted OR^a (95% CI)
Patients with pre-existing PVD	2.511*** (2.040∼3.091)	2.603*** (2.105∼3.220)
Patients with Meniere’s disease	1.746* (1.107∼2.752)	1.801* (1.136∼2.858)
Patients with benign paroxysmal positional vertigo	2.175** (1.233∼3.837)	2.201** (1.245∼3.891)
Patients with vestibular neuritis	2.325** (1.308∼4.133)	2.439** (1.360∼4.373)
Patients with other PVD	2.974*** (2.279∼3.880)	3.099*** (2.365∼4.061)
Controls	1.000	1.000

CI, confidence interval; OR, odds ratio; PVD, peripheral vestibular disorders; ^aAdjusted for age, monthly income, geographic location, urbanization level, hyperlipidemia, coronary heart disease, diabetes, hypertension, and hearing loss; *p < 0.05; **p < 0.01; ***p < 0.001.

DISCUSSION

Using a comprehensive dataset in Taiwan, we found that pre-existing peripheral vestibular disorders were associated with a higher likelihood of developing young-onset dementia. This robust association persisted after accounting for a comprehensive set of potential covariates and when examining the link between each type of peripheral vestibular disorders and the outcome. Study findings provide new insights into the possible role of vestibular dysfunction in the development of young-onset dementia. This potential pathophysiological link warrants future mechanistic investigation. To our knowledge, this is the first investigation into the role of peripheral vestibular disorders in young-onset dementia that occurred in individuals under 65 years of age. Young-onset dementia poses substantial personal, familiar, and economic burdens, given that it occurs during the most productive years of those affected. Its atypical symptoms and varied etiology make timely diagnosis and treatment particularly challenging. Vestibular health may be an important consideration in the early detection and management of this life-altering condition.

The degeneration of the medial-temporal region, implicated in the development of Alzheimer’s disease, has been shown to result from damage to the vestibular system. 7 Several studies further support the relationship between vestibular function and cognitive disorders.8,9, 8,9 Specifically, vestibular impairment contributes significantly to declines in spatial cognitive ability in patients with Alzheimer’s disease, independent of general cognitive decline. 10 Furthermore, balance and mobility challenges, coupled with the fear of falling or experiencing dizziness due to chronic vestibular disorders can create a cascading effect on an individual’s behavior, leading to reduced physical activity and social interaction, potentially exacerbating cognitive decline. 11 A more recent study by Bosmans et al. found that vestibular and balance dysfunctions are more prevalent in individuals with increasing cognitive decline, with Alzheimer’s disease patients showing delayed p13 latency in cervical vestibular-evoked myogenic potentials compared to healthy controls and those with mild cognitive impairment. 12 Additionally, clinical balance assessments indicated worse balance scores in more cognitively impaired groups, highlighting the potential of vestibular assessment in early dementia screening.

The complex mechanisms that underlie the relationship between peripheral vestibular disorders and dementia are likely multifactorial. Shared pathophysiological pathways, notably inflammation and oxidative stress, which are prevalent in both vestibular disorders and neurodegenerative diseases, may play a key role in this association. 13 Additionally, sensory deprivation resulting from vestibular dysfunction could lead to compensatory neuroplastic changes that affect cognitive functions. 14

Different forms of chronic peripheral vestibular disorders may have detrimental impacts on brain function as time progresses. Meniere’s disease, distinguished by intermittent vertigo, tinnitus, and hearing issues, has been associated with cognitive impairment, and the hearing impairment in Meniere’s disease could further contribute to cognitive deterioration. 15 Benign paroxysmal positional vertigo, the most common vestibular disorders, causes brief yet recurrent episodes of vertigo triggered by head position changes. The long-term consequences of episodic vertigo and balance impairment may indirectly impact brain structures involved in spatial navigation, memory, and cognitive processing. 16 Lastly, acute inflammatory conditions, such as vestibular neuritis, can provoke severe vertigo by abruptly disrupting the neural inputs essential for spatial orientation and memory-related functions. 2

Our findings provide new insights into young-onset dementia and are in general agreement with two recent studies. Hendriks and colleagues examined the risk factors associated with young-onset dementia in 356,052 participants in the UK Biobank. They found that alcohol use (versus abstinence), higher levels of formal education, and lower physical frailty (indicated by greater handgrip strength) were associated with a lowered risk of young-onset dementia. Conversely, having 2 APOE ɛ4 alleles, lower socioeconomic status, high CRP levels, orthostatic hypotension, stroke, diabetes, heart disease, depression, hearing impairment, vitamin D deficiency, alcohol use disorder, and social isolation were associated with an increased risk. 17 Although vestibular function was not directly assessed in this investigation, hearing impairment—a symptom associated with vestibular disorders—was linked to a 56% increased risk in the fully adjusted model. Another large-scale study of older adults aged 60 or above in South Korea showed that the respective presence of vestibular loss and hearing loss each slightly increased the risk of dementia (respective risk ratios = 1.084 and 1.074). 18 It is important to note that our study focused on young-onset dementia, a distinct category within the broader spectrum of dementia. This type of dementia has a more profound impact due to its onset at a younger age, which can have substantial ramifications on employment, financial stability, and family dynamics.

These findings emphasize the importance of considering vestibular health in patients with young-onset dementia. Early identification and management of vestibular symptoms could be pivotal in mitigating cognitive decline. Vestibular rehabilitation may be beneficial for patients with young-onset dementia and peripheral vestibular disorders, potentially halting or slowing cognitive deterioration. 19 A recent study by Tilky colleagues found that engaging in physical activities, sports, and exercises led to physical improvements (fitness, flexibility, and mobility) in patients with young-onset dementia. Alongside these physical benefits, participants experienced positive mental health outcomes, including improved memory for some and reduced anxiety and depression for the majority. 20 In light of these preliminary evidence, there is a clear need for further research to elucidate the causal mechanisms linking vestibular disorders with young-onset dementia and to assess whether proactive management of vestibular disorders might mitigate the risk of developing this condition.

There are several inherent limitations in this study. Firstly, the retrospective nature of the investigation, relying on data from Taiwan’s LHID2010, introduces potential risks of selection bias and information bias. The diagnostic criteria for young-onset dementia and peripheral vestibular disorders were based on ICD-9-CM and ICD-10-CM codes, which may not fully capture the complete spectrum of these conditions due to coding errors or variations across healthcare providers. Moreover, detailed clinical information such as dementia severity or lifestyle factors and genetic predispositions related to vestibular disorders were unavailable in the LHID2010 database, precluding a comprehensive investigation into their potential associations. While our analysis accounted for known confounders, such as age, sex, income status, geographic location, and comorbidities, using propensity score matching methods; there may be other unidentified factors that could affect the observed associations. Additionally, the generalizability of study findings is limited, as the study sample was drawn solely from a single national health insurance database in Taiwan. Lastly, the retrospective nature of this case-controlled observational study may preclude a definitive establishment of causality. Future prospective longitudinal studies with comprehensive clinical measures may further elucidate this association.

It should be noted that according to our design, individuals who were diagnosed with a peripheral vestibular disorder before the index date of their diagnosis of young-onset dementia were identified as having a preexisting condition of peripheral vestibular disorders. Consequently, cases presenting with a particular type of peripheral vertigo may initially be diagnosed and classified as a different form of peripheral vertigo, only to receive a more precise diagnosis of peripheral vertigo after some time. Since the initial classification code recorded in the health-insurance database will not be altered retroactively, the low number of patients with BPPV in our study data should be attributed to the study’s methodology rather than being considered the definitive diagnosis cases.

The link between peripheral vestibular disorders and subsequent young-onset dementia observed in this study has significant implications for clinical practice, particularly in the diagnostic precision and therapeutic management of young-onset dementia. Healthcare professionals should be mindful of the potential association between these conditions, especially among younger patients displaying cognitive symptoms. Early recognition and resolution of vestibular symptoms may not only improve these symptoms but also potentially slow down the cognitive deterioration associated with young-onset dementia. A multidisciplinary approach involving neurologists, otolaryngologists, and rehabilitation specialists could address the full spectrum of impairments to improve patient outcomes and quality of life. Future research into the mechanisms underlying this connection could advance innovative strategies for managing young-onset dementia.

In conclusion, this study identified a notable association between pre-existing peripheral vestibular disorders and young-onset dementia, suggesting that vestibular malfunction could play a crucial role in the early manifestation of dementia-related cognitive decline. These results underscore the importance of considering vestibular health in patients presenting with early cognitive decline. A comprehensive, interdisciplinary management strategy should be prioritized when treating patients with young-onset dementia.

AUTHOR CONTRIBUTIONS

Shih-Han Hung (Conceptualization; Writing – original draft; Writing – review & editing); Alison H Chang (Writing – original draft; Writing – review & editing); Yen-Fu Cheng (Writing – original draft; Writing – review & editing); Herng-Ching Lin (Conceptualization; Validation; Writing – original draft; Writing – review & editing); Chin-Shyan Chen (Conceptualization; Methodology; Validation; Writing – original draft; Writing – review & editing).

Footnotes

ACKNOWLEDGMENTS

The authors have no acknowledgments to report.

FUNDING

The authors have no funding to report.

CONFLICT OF INTEREST

The authors have no conflict of interest to report.

DATA AVAILABILITY

The data supporting the findings of this study can be obtained by interested researchers through a formal application process addressed to the HWDC, Department of Statistics, Ministry of Health and Welfare, Taiwan. These data were derived from the National Health Insurance Research Database, now managed by the Health and Welfare Data Science Center (HWDC) (, accessed on 2 January 2022).

References

Hendriks

, Peetoom

, Bakker

, et al. Global prevalence of young-onset dementia: a systematic review and meta-analysis. JAMA Neurol 2021; 78: 1080–1090.

Kelley

, Boeve

and Josephs

. Young-onset dementia: demographic and etiologic characteristics of 235 patients. Arch Neurol 2008; 65: 1502–1508.

Strupp

, Kim

, Murofushi

, et al. Bilateral vestibulopathy: Diagnostic criteria Consensus document of the Classification Committee of the Bárány Society 1. J Vestib Res 2017; 27: 177–189.

Bigelow

and Agrawal

. Vestibular involvement in cognition: Visuospatial ability, attention, executive function, and memory. J Vestib Res 2015; 25: 73–89.

, Lin

, Chuang

, et al. Association of dementia in patients with benign paroxysmal positional vertigo. Acta Neurol Scand 2017; 135: 197–203.

Kim

, Yoo

, Min

, et al. Increased risk of neurodegenerative dementia after benign paroxysmal positional vertigo. Int J Environ Res Public Health 2021; 18: 10553.

Previc

. Vestibular loss as a contributor to Alzheimer’s disease. Med Hypotheses 2013; 80: 360–367.

Nakamagoe

, Fujimiya

, Koganezawa

, et al. Vestibular function impairment in Alzheimer’s disease. J Alzheimers Dis 2015; 47: 185–196.

Yargholi

. Vestibulo-ocular reflex in patients with amnestic mild cognitive impairment and normal controls: a comparative study. Aud Vestib Res 2018; 27: 93–100.

10.

Wei

, Oh

, Harun

, et al. Vestibular loss predicts poorer spatial cognition in patients with Alzheimer’s disease. J Alzheimers Dis 2028; 61, 995–1003.

11.

Harun

, Oh

, Bigelow

, et al. Vestibular impairment in dementia. Otol Neurotol 2016; 37: 1137–1142.

12.

Bosmans

, Gommeren

, Gilles

, et al. Evidence of vestibular and balance dysfunction in patients with mild cognitive impairment and Alzheimer’s disease. Ear Hear 2024; 45: 53–61.

13.

Baloh

. Vertigo. Lancet 1998; 352: 1841–1846.

14.

Smith

, Darlington

and Zheng

. Move it or lose it—is stimulation of the vestibular system necessary for normal spatial memory? Hippocampus 2010; 20: 36–43.

15.

Lopez-Escamez

, Carey

, Chung

, et al. Diagnostic criteria for Menière’s disease. J Vestib Res 2015; 25: 1–7.

16.

von Brevern

, Radtke

, Lezius

, et al. Epidemiology of benign paroxysmal positional vertigo. A population-based study. J Neurol Neurosurg Psychiatry 2007; 78: 710–715.

17.

Hendriks

, Ranson

, Peetoom

, et al. Risk factors for young-onset dementia in UK Biobank participants: a prospective population-based study. JAMA Neurol 2024; 81: 134–142.

18.

Lim

, Son

, Chung

, et al. Relationship between vestibular loss and the risk of dementia using the 2002–2019 national insurance service survey in South Korea. Sci Rep 2023; 13: 16746.

19.

Cohen

, Kimball

and Adams

. Application of the vestibular disorders activities of daily living scale. Laryngoscope 2000; 110: 1204–1209.

20.

Tilki

, Curran

, Burton

, et al. Sport for confidence: a collaborative programme of physical activity, sport and exercise for people with young onset dementia. Work Older People 2023; 27: 128–136.