- Email: [email protected]
Association of early-onset dementia with activities of daily living (ADL) in middle-aged adults with intellectual disabilities: The caregiver's perspective
Research in Developmental Disabilities 35 (2014) 626–631
Contents lists available at ScienceDirect
Research in Developmental Disabilities
Association of early-onset dementia with activities of daily living (ADL) in middle-aged adults with intellectual disabilities: The caregiver’s perspective Lan-Ping Lin a,b,1, Shang-Wei Hsu c,d,1, Yi-Chen Hsia a, Chia-Ling Wu e, Cordia Chu a,f, Jin-Ding Lin a,e,f,* a
School of Public Health, National Defense Medical Center, Taipei, Taiwan Department of Senior Citizen Service Management, Ching-Kuo Institute of Management and Health, Keelung City, Taiwan Department of Healthcare Administration, Asia University, Taichung, Taiwan d Department of Public Health, China Medical University, Taichung, Taiwan e Chung-Hua Foundation for Persons with Intellectual Disabilities, New Taipei City, Taiwan f Centre for Environment and Population Health, Griffith University, Brisbane, Qld, Australia b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 29 December 2013 Accepted 30 December 2013 Available online 24 January 2014
Few studies have investigated in detail which factors influence activities of daily living (ADL) in adults with intellectual disabilities (ID) comorbid with/without dementia conditions. The objective of the present study was to describe the relation between early onset dementia conditions and progressive loss of ADL capabilities and to examine the influence of dementia conditions and other possible factors toward ADL scores in adults with ID. This study was part of the ‘‘Healthy Aging Initiatives for Persons with an Intellectual Disability in Taiwan: A Social Ecological Approach’’ project. We analyzed data from 459 adults aged 45 years or older with an ID regarding their early onset symptoms of dementia and their ADL profile based on the perspective of the primary caregivers. Results show that a significant negative correlation was found between dementia score and ADL score in a Pearson’s correlation test (r = 0.28, p < 0.001). The multiple linear regression model reported that factors of male gender (b = 4.187, p < 0.05), marital status (b = 4.79, p < 0.05), education level (primary: b = 5.544, p < 0.05; junior high or more: b = 8.147, p < 0.01), Down’s syndrome (b = 9.290, p < 0.05), severe or profound disability level (b = 6.725, p < 0.05; b = 15.773, p < 0.001), comorbid condition (b = 4.853, p < 0.05) and dementia conditions (b = 9.245, p < 0.001) were variables that were able to significantly predict the ADL score (R2 = 0.241) after controlling for age. Disability level and comorbidity can explain 10% of the ADL score variation, whereas dementia conditions can only explain 3% of the ADL score variation in the study. The present study highlights that future studies should scrutinize in detail the reasons for the low explanatory power of dementia for ADL, particularly in examining the appropriateness of the measurement scales for dementia and ADL in aging adults with ID. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Activities of daily living (ADL) Aging Dementia Intellectual disability DSQIID
* Corresponding author at: School of Public Health, National Defense Medical Center, No. 161, Min-Chun East Road, Section 6, Nei-Hu, Taipei, Taiwan. Tel.: +886 2 87923100x18447; fax: +886 2 87923147. E-mail addresses: [email protected], [email protected] (J.-D. Lin). 1 Equally contributed to this paper. 0891-4222/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2013.12.015
L.-P. Lin et al. / Research in Developmental Disabilities 35 (2014) 626–631
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1. Introduction Dementia is an important determinant of functional status (Sauvaget, Yamada, Fujiwara, Sasaki, & Mimori, 2002), and persons with dementia usually have problems performing activities of daily living (ADL) due to episodic memory decline (Mokhtari et al., 2012). There are also physical consequences of dementia: as the amyloids and neurodegeneration that affect memory and cognition take hold, motor control deteriorates (Marshall, Amariglio, Sperling, & Rentz, 2012). As longevity increases for persons with ID, research continues to explore ways to improve health outcomes and, in particular, to address the challenges posed by dementia (McCalliona & McCarron, 2004). Alzheimer’s Disease International (2003) revealed that the prevalence of dementia among people with ID appears to be about the same as in the general population, which is approximately 5% of people aged 65 and older. However, in service practice, most disability institution managers agreed that people with ID experienced earlier onset of aging characteristics (Lin, Wu, Lin, Lin, & Chu, 2011). Strydom, Hassiotis, King, and Livingston (2009) also indicated that the overall prevalence of criteria-defined dementia cases was 13.1% in those aged 60 and older and 18.3% in those aged more than 65 years. The researchers concluded that adults with ID are more likely than the general population to develop cognitive decline and dementia. Functional impairment is a core symptom of dementia often measured by loss of the ability to perform ADL (Arrighi, Ge´linas, McLaughlin, Buchanan, & Gauthier, 2013). However, few studies have investigated in detail which factors influence ADL in adults with ID comorbid with/without dementia conditions. The objective of the present study was to describe the relation between early onset dementia conditions and progressive loss of ADL capabilities expressed by adults with ID based on the primary caregivers’ perspective. Furthermore, we used stepwise multiple linear regression analyses to examine the influence of dementia conditions and other possible factors toward the ADL score in adults with ID. 2. Methods This study was part of the ‘‘Healthy Aging Initiatives for Persons with an Intellectual Disability in Taiwan: A Social Ecological Approach’’ project (Lin et al., 2013b). A cross-sectional survey was conducted to recruit community residents with ID. We analyzed data from 459 adults aged 45 years or older with an ID about their early onset symptoms of dementia and their activities of daily living (ADL) profile based on the perspective of the primary caregivers. To measure early onset aging conditions, the Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) was administered to the caregivers to determine the symptoms of dementia in the adults with ID. There are three parts of the DSQIID scale, which contain 53 items that evaluate a change from a person’s ‘‘normal’’ level of functioning; these items consider areas such as loss of memory, confusion, loss of skills, social withdrawal, behavioral changes, psychological symptoms, physical symptoms, sleep disturbance and speech abnormalities (Deb, Hare, Prior, & Bhaumik, 2007). This study used the Barthel Index (BI), commonly referred to as ADL, to determine a baseline level of functional limitation in adults with ID. The BI or ADL is a 10-item scale that includes assessments of independence for bowels, bladder, grooming, toilet use, feeding, transfers, mobility, dressing, stairs and bathing (Mahoney & Barthel, 1965). The detailed results of DSQIID and ADL in adults with ID were described in our previous papers (Lin, Hsia, Hsu, Wu, & Lin, 2013a; Lin, Lin, Hsia, Hsu, Wu, & Chu, 2014). The analyses of the present paper infer that functional limitations were the consequences of early onset dementia conditions in adults with ID in the study. Therefore, we describe the correlations between dementia and ADL, and then examine the possible factors associated with ADL scores by controlling for other demographic factors in multiple linear regression models. 3. Results Table 1 describes the demographic characteristics of the ID individuals; 51.6% of respondents were male and 48.4% were female. The mean age of ID adults was 55 years (range = 45.4–83.8 years). Most of the ID adults were never unmarried (61.9%). Nearly half of the adults with ID were illiterate or accepted informal education, 34.7% had finished primary school and 15.5% had completed junior high school or higher. With regard to disability level, 17.4% and 32.4% of ID adults had a mild or moderate level of disability, respectively, with severe or profound disability accounting for 34.8% and 15.4% of the sample, respectively. Among the sample, 6.6% of respondents with ID had Down’s syndrome, and 25.9% of respondents had a comorbid diagnosis of mental or neurological diseases. Table 2 presents the data on dementia (DSQIID score) and the distribution of ADL scores for the adults with ID. Each response on the DSQIID scale that presents an indication of change or a new symptom is scored as 1 or 0 (53 scores total). A cut-off score of 20 on the scale yields a high sensitivity and specificity when used for adults with an ID, and therefore a score of 20 shows a possibility of dementia (Deb et al., 2007). This study’s results revealed that 16.3% of the adults with ID might have dementia conditions (DSQIID score 320). With regard to ADL measures, there are five categories of functional impairment using the following cut-off values in Taiwan: total dependence (BI score 0–20), severe dependence (BI score 21– 60), moderate dependence (BI score 61–90), mild dependence (BI score 91–99), and total independence (BI score 100) (Taiwan Department of Health, 2012). Results showed that 2.2% of adults with ID were in total dependence, 11.8% were in severe dependence, 28.1% were in moderate dependence, 7.8% had a mild dependence, and 50.1% were totally independent. A chi-squared test indicated that there was a significant correlation between dementia status and ADL categories in adults
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Table 1 Demographic characteristics of adults with ID (n = 459). Characteristics Gender (n = 459) Male Female Age (n = 451) 45–54 355 Marital status (n = 454) Unmarried Married Education level (n = 458) Illiterate/Informal Primary school Junior high school or more Down’s syndrome (n = 425) Yes No Disability level (n = 454) Mild Moderate Severe Profound Comorbidity status (n = 455) No Yes Mental illness Neurological disease
n
%
Mean S.D. (range)
237 222
51.6 48.4
263 188
58.3 41.7
281 173
61.9 38.1
228 159 71
49.8 34.7 15.5
28 397
6.6 93.4
79 147 158 70
17.4 32.4 34.8 15.4
337 118 79 56
74.1 25.9 58.5 41.5
55.0 7.6 (45.4–83.8)
Table 2 Description of dementia (DSQIID) and distribution of ADL scores for adults with ID (n = 459).
DSQIID No dementia (score <20) Dementia (score 320) ADL Total dependence (score 0–20) Severe dependence (score 21–60) Moderate dependence (score 61–90) Mild dependence (score 91–99) Total independence (score 100)
n
%
384 75
83.7 16.3
10 54 129 36 230
2.2 11.8 28.1 7.8 50.1
Mean S.D. (range) 10.4 9.4 (0–51)
86.3 20.9 (10–100)
with ID, as seen in Table 3 (p < 0.001). In addition, Table 4 shows that a significant negative correlation was found between dementia score (DSQIID) and ADL score in a Pearson’s correlation test (r = 0.28, p < 0.001). Finally, we tested the relation between dementia or other associated factors and ADL score by multiple linear regression analyses (Table 5). Model 1 indicated that marital status (b = 6.459, p < 0.01) and education level (primary: b = 9.379, p < 0.001; junior high or more: b = 13.484, p < 0.001) were variables able to significantly predict ADL score (R2 = 0.116), after controlling for gender and age. Model 2 revealed that male gender (b = 4.162, p < 0.05), age by year (b = 0.293, p < 0.05), marital status (b = 4.647, p < 0.05), education level (primary: b = 5.023, p < 0.05; junior high or more: b = 7.397, p < 0.05), Down’s syndrome status (b = 9.936, p < 0.05), severe or profound disability level (b = 7.084, p < 0.05; b = 16.214, p < 0.001) and comorbidity condition (b = 6.279, p < 0.01) can explain 22.1% of variation in ADL score. The full model reported that factors of male gender (b = 4.187, p < 0.05), marital status (b = 4.79, p < 0.05), education level Table 3 Chi-squared test of dementia status and ADL categories in adults with ID (n = 459). Characteristics
Total dependence Severe dependence Moderate dependence Mild dependence Total independence x2 n (%)
Dementia condition No dementia (score <20) 9 (2.3) Dementia (score 320) 1 (1.3)
n (%)
n (%)
n (%)
n (%)
34 (8.9) 20 (26.7)
97 (25.2) 32 (42.7)
34 (8.9) 2 (2.6)
210 (54.7) 20 (26.7)
p value
36.875 <0.001
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Table 4 Pearson’s correlation of dementia and ADL scores in adults with ID (n = 459). Dementia score Dementia score ADL score *
ADL score 0.28*
1 1
p < 0.001.
Table 5 Multiple linear regression models of ADL scores and dementia conditions or other associated factors in adults with ID. Variable (reference)
Model 1 (n = 445)
b (S.E.) Constant Gender (female) Age Marital status (unmarried) Education level (illiterate/informal) Primary school Junior high school or more Down’s syndrome (no) Disability level (mild) Moderate Severe Profound Comorbidity status (no) Dementia (no)
Model 2 (n = 404)
b (S.E.)
t-test ***
Model 3 (n = 404) t-test ***
b (S.E.)
t-test
88.418 (7.649) 3.636 (2.073) 0.211 (0.134) 6.459 (2.189)
11.559 1.754 1.576 2.951**
102.926 (8.231) 4.162 (2.086) -0.293 (0.135) 4.647 (2.234)
12.504 1.995* 2.178* 2.080*
100.067 (8.142) 4.187 (2.054) 0.233 (0.133) 4.790 (2.200)
12.291*** 2.039* 1.749 2.177*
9.379 (2.129) 13.484 (2.885)
4.405*** 4.674***
5.023 (2.209) 7.397 (3.054) 9.936 (3.882)
2.274* 2.422* 2.560*
5.544 (2.180) 8.147 (3.013) 9.290 (3.826)
2.543* 2.704** 2.428*
<0.001 (2.746) 7.084 (2.794) 16.214 (3.571) 6.279 (2.191)
<0.001 2.536* 4.541*** 2.866**
0.433 (2.706) 6.725 (2.752) 15.773 (3.517) 4.853 (2.192) 9.245 (2.522)
0.160 2.444* 4.484*** 2.214* 3.666***
Model 1: R2 = 0.116; Model 2: R2 = 0.215; Model 3: R2 = 0.241. * p < 0.05. ** p < 0.01. *** p < 0.001.
(primary: b = 5.544, p < 0.05; junior high or more: b = 8.147, p < 0.01), Down’s syndrome status (b = 9.290, p < 0.05), severe or profound disability level (b = 6.725, p < 0.05; b = 15.773, p < 0.001), comorbidity condition (b = 4.853, p < 0.05) and dementia conditions (b = 9.245, p < 0.001) were variables able to significantly predict ADL score (R2 = 0.241) after controlling for age. However, the results illustrated that the dementia conditions can only explain 2% (an increase from 21.5% in model 2 to 24.1% in model 3) of the variation in ADL score in the study. 4. Discussion Dementia is characterized by deterioration in the ability to perform ADL in addition to loss of cognitive function and behavioral changes (Potkin, 2002). As dementia progresses there is a steady deterioration of the capacity to perform activities necessary to live independently. Older adults with cognitive impairment often have difficulties in remembering the proper sequence of ADL or how to use the tools necessary to perform ADL (Begum, Wang, Huq, & Mihailidis, 2013). The present paper aimed to provide information related to the relation between dementia conditions and ADL in adults with ID. We used a scale of DSQIID to measure early-onset dementia among adults with ID. Originally, the DSQIID was developed using data from adults with Down’s syndrome; the author confirms that it can be used with adults who have an ID who do not have Down’s syndrome (Deb et al., 2007), and it was recommended as a useful clinical tool to allow early detection and ongoing monitoring of dementia in older adults with ID (LifeSpan Newsletters, 2008). With regard to measures of daily activities in adults with ID, the BI-ADL is a valid measure of functional limitations and has been proposed as an appropriate index for clinical and research purposes (Collin, Wade, Davies, & Horne, 1988; Duffy, Gajree, Langhorne, Stott, & Quinn, 2013; Wade & Collin, 1988). Total scores of the modified BI may range from 0 to 100, with higher scores indicating greater independence (Collin et al., 1988). This index provides multifaceted constructs (Desai, Grossberg, & Sheth, 2004) and can be used to monitor improvement in daily activities over time. The present study’s results indicated that a significant negative correlation was found between dementia score (DSQIID) and ADL score, meaning that the occurrence of dementia conditions will increase functional limitations in the study respondents. Martyr and Clare (2012) conducted a meta-analysis suggesting a consistent moderate association between ADL and executive function in early dementia. Sonn (1996) revealed that physical impairments and functional limitations had a considerable impact on dependence in daily life activities as persons dependent in ADL had lower maximal walking speed, grip strength, knee extensor strength, stair-climbing capacity and forward reach than those who were independent in ADL. Crespo, Hornillos, and de Quiro´s (2013) highlighted that the quality of life perception by persons with dementia living in a nursing home is mainly affected by their emotional state and functional autonomy in daily living. All the above studies concluded that there is a negative relationship between dementia condition and ADL capacity.
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The multiple linear regression models of ADL scores in this study found that factors of male gender, marital status, education level, Down’s syndrome, disability level, comorbidity and dementia conditions were variables able to significantly predict ADL score (R2 = 0.241) after controlling for age. In particular, the factors of disability level and comorbidity can explain 10% of the ADL score variation. However, the results illustrated that dementia conditions can only explain 3% of the variations in ADL score in the study. Possible reasons may be the younger age of the study sample or the appropriateness of the measurement scale for functional limitations. However, future studies should examine the low explanatory power of dementia for ADL among adults with ID. Compared with other studies, Desai et al. (2004) found that functional decline in patients with dementia can also result from causes other than dementia, such as comorbid medical and psychiatric illnesses and sensory impairment. Strydom et al. (2009) found that prevalence rates did not differ between mild, moderate and severe ID groups, and they concluded that age was a strong risk factor and was not influenced by sex or ID severity. Dementia, even after adjusting for age, gender and history of stroke, was a strong predictor of functional disability, as indicated by ADL or IADL status (Sauvaget et al., 2002). In Korea, Ha and Kim (2013) identified the factors that influence ADL to be fecal and urinary incontinence, regularity of exercise, Mini-Mental State Examination score and stroke history in the elderly with probable dementia. These five variables explained 30.8% of the ADL score for the elderly with probable dementia. Arrighi et al. (2013) concluded that ADL are impacted in a progressive and hierarchical manner associated with cognitive decline, but substantial variability remains among individuals, as well as in the relative order of items affected. In addition to demographic factors, disease duration, and depression, neuropsychological variables are valuable predictors of functional status in Alzheimer’s patients in an early disease stage (Benke et al., 2013). Because people with ID have communication and writing difficulties, the present study measured the relation between dementia and ADL of adults with ID based on the primary caregiver’s perspective. This type of proxy perspective may not fully represent ID individuals’ conditions. Another limitation of the study is that a cross-sectional design lacks the ability to detect a causal relationship between dementia and ADL. However, the present study provides some of the first data to examine dementia or associated factors and ADL among adults with ID. As Venturelli, Scarsini, and Schena (2011) indicated, it is possible to improve quality of life for aging adults with ID by stabilizing progressive cognitive dysfunction through health promotion programs. Such interventions should also aim to improve physical and mental health statuses and promote social and interpersonal interactions. These activities promote cognitive function, contribute to the prevention of dementia (Ha & Kim, 2013) and decrease functional limitations in adults with ID. Acknowledgments This research was financially supported by the National Science Council, research title ‘‘Healthy Aging Initiatives for Persons with Intellectual Disabilities in Taiwan: A Social Ecological Approach (grant no. NSC 101-2314-B-016-026-MY3)’’. We would also like to thank the caregivers of people with intellectual disabilities who participated in the study. References Alzheimer’s Disease International. (2003). Why the concern about dementia among people with intellectual disabilities? Dementia and intellectual disabilities, London, United Kingdom: Alzheimer’s Disease International Information Sheet 11. Arrighi, H. M., Ge´linas, I., McLaughlin, T. P., Buchanan, J., & Gauthier, S. (2013). Longitudinal changes in functional disability in Alzheimer’s disease patients. International Psychogeriatrics, 25, 929–937. Begum, M., Wang, R., Huq, R., & Mihailidis, A. (2013). Performance of daily activities by older adults with dementia: The role of an assistive robot. IEEE International Conference on Rehabilitation Robotics Proceedings, 1–8. http://dx.doi.org/10.1109/ICORR.2013.6650405 Benke, T., Delazer, M., Sanin, G., Schmidt, H., Seiler, S., Ransmayr, G., Dal-Bianco, P., Uranu¨s, M., Marksteiner, J., Leblhuber, F., Kapeller, P., Bancher, C., & Schmidt, R. (2013). Cognition, gender, and functional abilities in Alzheimer’s disease: How are they related? Journal of Alzheimer’s Disease, 35, 247–252. Collin, C., Wade, D. T., Davies, S., & Horne, V. (1988). The Barthel ADL Index: A reliability study. International Disability Studies, 10, 61–63. Crespo, M., Hornillos, C., & de Quiro´s, M. B. (2013). Factors associated with quality of life in dementia patients in long-term care. International Psychogeriatrics, 25, 577–585. Deb, S., Hare, M., Prior, L., & Bhaumik, S. (2007). Dementia screening questionnaire for individuals with intellectual disabilities. British Journal of Psychiatry, 190, 440–444. Desai, A. K., Grossberg, G. T., & Sheth, D. N. (2004). Activities of daily living in patients with dementia: clinical relevance, methods of assessment and effects of treatment. CNS Drugs, 18, 853–875. Duffy, L., Gajree, S., Langhorne, P., Stott, D. J., & Quinn, T. J. (2013). Reliability (inter-rater agreement) of the Barthel Index for assessment of stroke survivors: Systematic review and meta-analysis. Stroke, 44, 462–468. Ha, E., & Kim, K. (2013). Factors that influence activities of daily living in the elderly with probable dementia. Journal of Psychiatric and Mental Health Nursing http:// dx.doi.org/10.1111/jpm.12110. Epub ahead of print LifeSpan Newsletters. (2008). Resource review: Dementia screening questionnaire for individuals with ID (DSQIID). Melbourne, Vic: Monash University. Lin, L. P., Hsia, Y. C., Hsu, S. W., Wu, C. L., & Lin, J. D. (2013). Caregivers’ reported functional limitations in activities of daily living among middle-aged adults with intellectual disabilities. Research in Developmental Disabilities, 34, 4559–4564. Lin, J. D., Lin, L. P., Hsia, Y. C., Hsu, S. W., Wu, C. L., & Chu, C. (2014). A national survey of caregivers’ perspective of early symptoms of dementia among adults with an intellectual disability based on the DSQIID scale. Research in Autism Spectrum Disorders, 8, 275–280. Lin, J. D., Lin, L. P., Hsu, S. W., Chou, Y. C., Lin, F. G., Hsu, C. H., Lai, C. I., & Wu, J. L. (2013). Healthy aging initiatives for persons with intellectual disabilities in Taiwan: A social ecological approach. Research report of National Science Council, Taipei, Taiwan, Republic of China. Grant no NSC 101-2314-B-016-026-MY3. Lin, J. D., Wu, C. L., Lin, P. Y., Lin, L. P., & Chu, C. M. (2011). Early onset ageing and service preparation in people with intellectual disabilities: Institutional managers’ perspective. Research in Developmental Disabilities, 32, 188–193. Mahoney, F. I., & Barthel, D. W. (1965). Functional evaluation: The Barthel Index. Maryland State Medical Journal, 14, 61–65. Marshall, G. A., Amariglio, R. E., Sperling, R. A., & Rentz, D. M. (2012). Activities of daily living: Where do they fit in the diagnosis of Alzheimer’s disease? Neurodegenerative Disease Management, 2, 483–491.
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Martyr, A., & Clare, L. (2012). Executive function and activities of daily living in Alzheimer’s disease: A correlational meta-analysis. Dementia and Geriatric Cognitive Disorders, 33, 189–203. McCalliona, P., & McCarron, M. (2004). Ageing and intellectual disabilities: A review of recent literature. Current Opinion in Psychiatry, 17, 349–352. Mokhtari, M., Aloulou, H., Tiberghien, T., Biswas, J., Racoceanu, D., & Yap, P. (2012). New trends to support independence in persons with mild dementia: A minireview. Gerontology, 58, 554–563. Potkin, S. G. (2002). The ABC of Alzheimer’s disease: ADL and improving day-to-day functioning of patients. International Psychogeriatrics, 14, 7–26. Sauvaget, C., Yamada, M., Fujiwara, S., Sasaki, H., & Mimori, Y. (2002). Dementia as a predictor of functional disability: A four-year follow-up study. Gerontology, 48, 226–233. Sonn, U. (1996). Longitudinal studies of dependence in daily life activities among elderly persons. Scandinavian Journal of Rehabilitation Medicine, 34, 1–35. Strydom, A., Hassiotis, A., King, M., & Livingston, G. (2009). The relationship of dementia prevalence in older adults with intellectual disability (ID) to age and severity of ID. Psychological Medicine, 39, 13–21. Taiwan Department of Health. (2012). Modified disease and disability diagnosis certification for application of foreign caregivers. Taiwan Department of Health: Taipei, Taiwan, Republic of China. DOH License no. 1012863831, issued on September 24, 2012. Venturelli, M., Scarsini, R., & Schena, F. (2011). Six-month walking program changes cognitive and ADL performance in patients with Alzheimer. American Journal of Alzheimer’s Disease and Other Dementias, 26, 381–388. Wade, D. T., & Collin, C. (1988). The Barthel ADL Index: A standard measure of physical disability? International Disability Studies, 10, 64–67.
Contents lists available at ScienceDirect
Research in Developmental Disabilities
Association of early-onset dementia with activities of daily living (ADL) in middle-aged adults with intellectual disabilities: The caregiver’s perspective Lan-Ping Lin a,b,1, Shang-Wei Hsu c,d,1, Yi-Chen Hsia a, Chia-Ling Wu e, Cordia Chu a,f, Jin-Ding Lin a,e,f,* a
School of Public Health, National Defense Medical Center, Taipei, Taiwan Department of Senior Citizen Service Management, Ching-Kuo Institute of Management and Health, Keelung City, Taiwan Department of Healthcare Administration, Asia University, Taichung, Taiwan d Department of Public Health, China Medical University, Taichung, Taiwan e Chung-Hua Foundation for Persons with Intellectual Disabilities, New Taipei City, Taiwan f Centre for Environment and Population Health, Griffith University, Brisbane, Qld, Australia b c
A R T I C L E I N F O
A B S T R A C T
Article history: Received 29 December 2013 Accepted 30 December 2013 Available online 24 January 2014
Few studies have investigated in detail which factors influence activities of daily living (ADL) in adults with intellectual disabilities (ID) comorbid with/without dementia conditions. The objective of the present study was to describe the relation between early onset dementia conditions and progressive loss of ADL capabilities and to examine the influence of dementia conditions and other possible factors toward ADL scores in adults with ID. This study was part of the ‘‘Healthy Aging Initiatives for Persons with an Intellectual Disability in Taiwan: A Social Ecological Approach’’ project. We analyzed data from 459 adults aged 45 years or older with an ID regarding their early onset symptoms of dementia and their ADL profile based on the perspective of the primary caregivers. Results show that a significant negative correlation was found between dementia score and ADL score in a Pearson’s correlation test (r = 0.28, p < 0.001). The multiple linear regression model reported that factors of male gender (b = 4.187, p < 0.05), marital status (b = 4.79, p < 0.05), education level (primary: b = 5.544, p < 0.05; junior high or more: b = 8.147, p < 0.01), Down’s syndrome (b = 9.290, p < 0.05), severe or profound disability level (b = 6.725, p < 0.05; b = 15.773, p < 0.001), comorbid condition (b = 4.853, p < 0.05) and dementia conditions (b = 9.245, p < 0.001) were variables that were able to significantly predict the ADL score (R2 = 0.241) after controlling for age. Disability level and comorbidity can explain 10% of the ADL score variation, whereas dementia conditions can only explain 3% of the ADL score variation in the study. The present study highlights that future studies should scrutinize in detail the reasons for the low explanatory power of dementia for ADL, particularly in examining the appropriateness of the measurement scales for dementia and ADL in aging adults with ID. ß 2014 Elsevier Ltd. All rights reserved.
Keywords: Activities of daily living (ADL) Aging Dementia Intellectual disability DSQIID
* Corresponding author at: School of Public Health, National Defense Medical Center, No. 161, Min-Chun East Road, Section 6, Nei-Hu, Taipei, Taiwan. Tel.: +886 2 87923100x18447; fax: +886 2 87923147. E-mail addresses: [email protected], [email protected] (J.-D. Lin). 1 Equally contributed to this paper. 0891-4222/$ – see front matter ß 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ridd.2013.12.015
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1. Introduction Dementia is an important determinant of functional status (Sauvaget, Yamada, Fujiwara, Sasaki, & Mimori, 2002), and persons with dementia usually have problems performing activities of daily living (ADL) due to episodic memory decline (Mokhtari et al., 2012). There are also physical consequences of dementia: as the amyloids and neurodegeneration that affect memory and cognition take hold, motor control deteriorates (Marshall, Amariglio, Sperling, & Rentz, 2012). As longevity increases for persons with ID, research continues to explore ways to improve health outcomes and, in particular, to address the challenges posed by dementia (McCalliona & McCarron, 2004). Alzheimer’s Disease International (2003) revealed that the prevalence of dementia among people with ID appears to be about the same as in the general population, which is approximately 5% of people aged 65 and older. However, in service practice, most disability institution managers agreed that people with ID experienced earlier onset of aging characteristics (Lin, Wu, Lin, Lin, & Chu, 2011). Strydom, Hassiotis, King, and Livingston (2009) also indicated that the overall prevalence of criteria-defined dementia cases was 13.1% in those aged 60 and older and 18.3% in those aged more than 65 years. The researchers concluded that adults with ID are more likely than the general population to develop cognitive decline and dementia. Functional impairment is a core symptom of dementia often measured by loss of the ability to perform ADL (Arrighi, Ge´linas, McLaughlin, Buchanan, & Gauthier, 2013). However, few studies have investigated in detail which factors influence ADL in adults with ID comorbid with/without dementia conditions. The objective of the present study was to describe the relation between early onset dementia conditions and progressive loss of ADL capabilities expressed by adults with ID based on the primary caregivers’ perspective. Furthermore, we used stepwise multiple linear regression analyses to examine the influence of dementia conditions and other possible factors toward the ADL score in adults with ID. 2. Methods This study was part of the ‘‘Healthy Aging Initiatives for Persons with an Intellectual Disability in Taiwan: A Social Ecological Approach’’ project (Lin et al., 2013b). A cross-sectional survey was conducted to recruit community residents with ID. We analyzed data from 459 adults aged 45 years or older with an ID about their early onset symptoms of dementia and their activities of daily living (ADL) profile based on the perspective of the primary caregivers. To measure early onset aging conditions, the Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) was administered to the caregivers to determine the symptoms of dementia in the adults with ID. There are three parts of the DSQIID scale, which contain 53 items that evaluate a change from a person’s ‘‘normal’’ level of functioning; these items consider areas such as loss of memory, confusion, loss of skills, social withdrawal, behavioral changes, psychological symptoms, physical symptoms, sleep disturbance and speech abnormalities (Deb, Hare, Prior, & Bhaumik, 2007). This study used the Barthel Index (BI), commonly referred to as ADL, to determine a baseline level of functional limitation in adults with ID. The BI or ADL is a 10-item scale that includes assessments of independence for bowels, bladder, grooming, toilet use, feeding, transfers, mobility, dressing, stairs and bathing (Mahoney & Barthel, 1965). The detailed results of DSQIID and ADL in adults with ID were described in our previous papers (Lin, Hsia, Hsu, Wu, & Lin, 2013a; Lin, Lin, Hsia, Hsu, Wu, & Chu, 2014). The analyses of the present paper infer that functional limitations were the consequences of early onset dementia conditions in adults with ID in the study. Therefore, we describe the correlations between dementia and ADL, and then examine the possible factors associated with ADL scores by controlling for other demographic factors in multiple linear regression models. 3. Results Table 1 describes the demographic characteristics of the ID individuals; 51.6% of respondents were male and 48.4% were female. The mean age of ID adults was 55 years (range = 45.4–83.8 years). Most of the ID adults were never unmarried (61.9%). Nearly half of the adults with ID were illiterate or accepted informal education, 34.7% had finished primary school and 15.5% had completed junior high school or higher. With regard to disability level, 17.4% and 32.4% of ID adults had a mild or moderate level of disability, respectively, with severe or profound disability accounting for 34.8% and 15.4% of the sample, respectively. Among the sample, 6.6% of respondents with ID had Down’s syndrome, and 25.9% of respondents had a comorbid diagnosis of mental or neurological diseases. Table 2 presents the data on dementia (DSQIID score) and the distribution of ADL scores for the adults with ID. Each response on the DSQIID scale that presents an indication of change or a new symptom is scored as 1 or 0 (53 scores total). A cut-off score of 20 on the scale yields a high sensitivity and specificity when used for adults with an ID, and therefore a score of 20 shows a possibility of dementia (Deb et al., 2007). This study’s results revealed that 16.3% of the adults with ID might have dementia conditions (DSQIID score 320). With regard to ADL measures, there are five categories of functional impairment using the following cut-off values in Taiwan: total dependence (BI score 0–20), severe dependence (BI score 21– 60), moderate dependence (BI score 61–90), mild dependence (BI score 91–99), and total independence (BI score 100) (Taiwan Department of Health, 2012). Results showed that 2.2% of adults with ID were in total dependence, 11.8% were in severe dependence, 28.1% were in moderate dependence, 7.8% had a mild dependence, and 50.1% were totally independent. A chi-squared test indicated that there was a significant correlation between dementia status and ADL categories in adults
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Table 1 Demographic characteristics of adults with ID (n = 459). Characteristics Gender (n = 459) Male Female Age (n = 451) 45–54 355 Marital status (n = 454) Unmarried Married Education level (n = 458) Illiterate/Informal Primary school Junior high school or more Down’s syndrome (n = 425) Yes No Disability level (n = 454) Mild Moderate Severe Profound Comorbidity status (n = 455) No Yes Mental illness Neurological disease
n
%
Mean S.D. (range)
237 222
51.6 48.4
263 188
58.3 41.7
281 173
61.9 38.1
228 159 71
49.8 34.7 15.5
28 397
6.6 93.4
79 147 158 70
17.4 32.4 34.8 15.4
337 118 79 56
74.1 25.9 58.5 41.5
55.0 7.6 (45.4–83.8)
Table 2 Description of dementia (DSQIID) and distribution of ADL scores for adults with ID (n = 459).
DSQIID No dementia (score <20) Dementia (score 320) ADL Total dependence (score 0–20) Severe dependence (score 21–60) Moderate dependence (score 61–90) Mild dependence (score 91–99) Total independence (score 100)
n
%
384 75
83.7 16.3
10 54 129 36 230
2.2 11.8 28.1 7.8 50.1
Mean S.D. (range) 10.4 9.4 (0–51)
86.3 20.9 (10–100)
with ID, as seen in Table 3 (p < 0.001). In addition, Table 4 shows that a significant negative correlation was found between dementia score (DSQIID) and ADL score in a Pearson’s correlation test (r = 0.28, p < 0.001). Finally, we tested the relation between dementia or other associated factors and ADL score by multiple linear regression analyses (Table 5). Model 1 indicated that marital status (b = 6.459, p < 0.01) and education level (primary: b = 9.379, p < 0.001; junior high or more: b = 13.484, p < 0.001) were variables able to significantly predict ADL score (R2 = 0.116), after controlling for gender and age. Model 2 revealed that male gender (b = 4.162, p < 0.05), age by year (b = 0.293, p < 0.05), marital status (b = 4.647, p < 0.05), education level (primary: b = 5.023, p < 0.05; junior high or more: b = 7.397, p < 0.05), Down’s syndrome status (b = 9.936, p < 0.05), severe or profound disability level (b = 7.084, p < 0.05; b = 16.214, p < 0.001) and comorbidity condition (b = 6.279, p < 0.01) can explain 22.1% of variation in ADL score. The full model reported that factors of male gender (b = 4.187, p < 0.05), marital status (b = 4.79, p < 0.05), education level Table 3 Chi-squared test of dementia status and ADL categories in adults with ID (n = 459). Characteristics
Total dependence Severe dependence Moderate dependence Mild dependence Total independence x2 n (%)
Dementia condition No dementia (score <20) 9 (2.3) Dementia (score 320) 1 (1.3)
n (%)
n (%)
n (%)
n (%)
34 (8.9) 20 (26.7)
97 (25.2) 32 (42.7)
34 (8.9) 2 (2.6)
210 (54.7) 20 (26.7)
p value
36.875 <0.001
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Table 4 Pearson’s correlation of dementia and ADL scores in adults with ID (n = 459). Dementia score Dementia score ADL score *
ADL score 0.28*
1 1
p < 0.001.
Table 5 Multiple linear regression models of ADL scores and dementia conditions or other associated factors in adults with ID. Variable (reference)
Model 1 (n = 445)
b (S.E.) Constant Gender (female) Age Marital status (unmarried) Education level (illiterate/informal) Primary school Junior high school or more Down’s syndrome (no) Disability level (mild) Moderate Severe Profound Comorbidity status (no) Dementia (no)
Model 2 (n = 404)
b (S.E.)
t-test ***
Model 3 (n = 404) t-test ***
b (S.E.)
t-test
88.418 (7.649) 3.636 (2.073) 0.211 (0.134) 6.459 (2.189)
11.559 1.754 1.576 2.951**
102.926 (8.231) 4.162 (2.086) -0.293 (0.135) 4.647 (2.234)
12.504 1.995* 2.178* 2.080*
100.067 (8.142) 4.187 (2.054) 0.233 (0.133) 4.790 (2.200)
12.291*** 2.039* 1.749 2.177*
9.379 (2.129) 13.484 (2.885)
4.405*** 4.674***
5.023 (2.209) 7.397 (3.054) 9.936 (3.882)
2.274* 2.422* 2.560*
5.544 (2.180) 8.147 (3.013) 9.290 (3.826)
2.543* 2.704** 2.428*
<0.001 (2.746) 7.084 (2.794) 16.214 (3.571) 6.279 (2.191)
<0.001 2.536* 4.541*** 2.866**
0.433 (2.706) 6.725 (2.752) 15.773 (3.517) 4.853 (2.192) 9.245 (2.522)
0.160 2.444* 4.484*** 2.214* 3.666***
Model 1: R2 = 0.116; Model 2: R2 = 0.215; Model 3: R2 = 0.241. * p < 0.05. ** p < 0.01. *** p < 0.001.
(primary: b = 5.544, p < 0.05; junior high or more: b = 8.147, p < 0.01), Down’s syndrome status (b = 9.290, p < 0.05), severe or profound disability level (b = 6.725, p < 0.05; b = 15.773, p < 0.001), comorbidity condition (b = 4.853, p < 0.05) and dementia conditions (b = 9.245, p < 0.001) were variables able to significantly predict ADL score (R2 = 0.241) after controlling for age. However, the results illustrated that the dementia conditions can only explain 2% (an increase from 21.5% in model 2 to 24.1% in model 3) of the variation in ADL score in the study. 4. Discussion Dementia is characterized by deterioration in the ability to perform ADL in addition to loss of cognitive function and behavioral changes (Potkin, 2002). As dementia progresses there is a steady deterioration of the capacity to perform activities necessary to live independently. Older adults with cognitive impairment often have difficulties in remembering the proper sequence of ADL or how to use the tools necessary to perform ADL (Begum, Wang, Huq, & Mihailidis, 2013). The present paper aimed to provide information related to the relation between dementia conditions and ADL in adults with ID. We used a scale of DSQIID to measure early-onset dementia among adults with ID. Originally, the DSQIID was developed using data from adults with Down’s syndrome; the author confirms that it can be used with adults who have an ID who do not have Down’s syndrome (Deb et al., 2007), and it was recommended as a useful clinical tool to allow early detection and ongoing monitoring of dementia in older adults with ID (LifeSpan Newsletters, 2008). With regard to measures of daily activities in adults with ID, the BI-ADL is a valid measure of functional limitations and has been proposed as an appropriate index for clinical and research purposes (Collin, Wade, Davies, & Horne, 1988; Duffy, Gajree, Langhorne, Stott, & Quinn, 2013; Wade & Collin, 1988). Total scores of the modified BI may range from 0 to 100, with higher scores indicating greater independence (Collin et al., 1988). This index provides multifaceted constructs (Desai, Grossberg, & Sheth, 2004) and can be used to monitor improvement in daily activities over time. The present study’s results indicated that a significant negative correlation was found between dementia score (DSQIID) and ADL score, meaning that the occurrence of dementia conditions will increase functional limitations in the study respondents. Martyr and Clare (2012) conducted a meta-analysis suggesting a consistent moderate association between ADL and executive function in early dementia. Sonn (1996) revealed that physical impairments and functional limitations had a considerable impact on dependence in daily life activities as persons dependent in ADL had lower maximal walking speed, grip strength, knee extensor strength, stair-climbing capacity and forward reach than those who were independent in ADL. Crespo, Hornillos, and de Quiro´s (2013) highlighted that the quality of life perception by persons with dementia living in a nursing home is mainly affected by their emotional state and functional autonomy in daily living. All the above studies concluded that there is a negative relationship between dementia condition and ADL capacity.
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The multiple linear regression models of ADL scores in this study found that factors of male gender, marital status, education level, Down’s syndrome, disability level, comorbidity and dementia conditions were variables able to significantly predict ADL score (R2 = 0.241) after controlling for age. In particular, the factors of disability level and comorbidity can explain 10% of the ADL score variation. However, the results illustrated that dementia conditions can only explain 3% of the variations in ADL score in the study. Possible reasons may be the younger age of the study sample or the appropriateness of the measurement scale for functional limitations. However, future studies should examine the low explanatory power of dementia for ADL among adults with ID. Compared with other studies, Desai et al. (2004) found that functional decline in patients with dementia can also result from causes other than dementia, such as comorbid medical and psychiatric illnesses and sensory impairment. Strydom et al. (2009) found that prevalence rates did not differ between mild, moderate and severe ID groups, and they concluded that age was a strong risk factor and was not influenced by sex or ID severity. Dementia, even after adjusting for age, gender and history of stroke, was a strong predictor of functional disability, as indicated by ADL or IADL status (Sauvaget et al., 2002). In Korea, Ha and Kim (2013) identified the factors that influence ADL to be fecal and urinary incontinence, regularity of exercise, Mini-Mental State Examination score and stroke history in the elderly with probable dementia. These five variables explained 30.8% of the ADL score for the elderly with probable dementia. Arrighi et al. (2013) concluded that ADL are impacted in a progressive and hierarchical manner associated with cognitive decline, but substantial variability remains among individuals, as well as in the relative order of items affected. In addition to demographic factors, disease duration, and depression, neuropsychological variables are valuable predictors of functional status in Alzheimer’s patients in an early disease stage (Benke et al., 2013). Because people with ID have communication and writing difficulties, the present study measured the relation between dementia and ADL of adults with ID based on the primary caregiver’s perspective. This type of proxy perspective may not fully represent ID individuals’ conditions. Another limitation of the study is that a cross-sectional design lacks the ability to detect a causal relationship between dementia and ADL. However, the present study provides some of the first data to examine dementia or associated factors and ADL among adults with ID. As Venturelli, Scarsini, and Schena (2011) indicated, it is possible to improve quality of life for aging adults with ID by stabilizing progressive cognitive dysfunction through health promotion programs. Such interventions should also aim to improve physical and mental health statuses and promote social and interpersonal interactions. These activities promote cognitive function, contribute to the prevention of dementia (Ha & Kim, 2013) and decrease functional limitations in adults with ID. Acknowledgments This research was financially supported by the National Science Council, research title ‘‘Healthy Aging Initiatives for Persons with Intellectual Disabilities in Taiwan: A Social Ecological Approach (grant no. NSC 101-2314-B-016-026-MY3)’’. We would also like to thank the caregivers of people with intellectual disabilities who participated in the study. References Alzheimer’s Disease International. (2003). Why the concern about dementia among people with intellectual disabilities? 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