**Adaptive Behaviour Change and Health in Adults with Down Syndrome: A Prospective Clinical Follow-Up Study**

T. Määttä, T. Tervo-Määttä, A. Taanila, M. Kaski and M. Iivanainen

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/57461

**1. Introduction**

People with Down syndrome are prone to early ageing and Alzheimer's disease (Zigman & Lott 2007). The functional decline in adults with Down syndrome starts decades earlier, compared to the mainstream population and other people with intellectual disabilities (Zigman *et al.* 1996; Strydom *et al.* 2007). The coping skills necessary for daily life, social interactions and work are gradually lost during the progression of dementia (Margallo-Lana *et al.* 2007).

Typical neuropathology of Alzheimer's disease is seen in virtually all people with Down syndrome by the age of 40 (Wisniewski *et al.* 1985). Depending on diagnostic criteria, 17-55% of them develop clinical dementia after that age (Holland *et al.* 2000; Janicki & Dalton 2000; Coppus *et al.* 2006). Genetic factors modifying the risk of dementia in adults with Down syndrome have been identified (Zigman & Lott 2007; Prasher *et al.* 2008; Patel *et al.* 2010). The rates of dementia in adults with intellectual disability without Down syndrome aged 60 years and older are greater than expected (Strydom *et al.* 2007).

The cognitive impairment in adults with Down syndrome has similarities to early cognitive changes in Alzheimer's disease (Brugge *et al.*1994). Personality and behaviour changes (Ball *et al.* 2006), executive dysfunction (Ball *et al.* 2008) and selective attention deficits (Krinsky-McHale *et al.* 2008) are early signs of dementia in adults with Down syndrome. Frontal-like

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dementia can be diagnosed in 33% in their thirties (Holland *et al.* 2000). Maladaptive behaviour is often seen and includes aggression, fearfulness, sadness, sleep problems, social inadequacy, stealing and general regressive behaviour (Urv *et al.* 2008). Increasing age associates with decreasing cognitive and language abilities; the deterioration with the age is largely explained by the presence of Alzheimer's disease (Iacono *et al.* 2010).

The aim of the present study was to explore the clinical usefulness of repeated assessments of adaptive behaviour in people with Down syndrome and suspected or confirmed dementia. Repeated assessments of adaptive behaviour in people at risk of functional decline might help to confirm the change and lead to necessary additional evaluations of the underlying reasons

Adaptive Behaviour Change and Health in Adults with Down Syndrome: A Prospective Clinical Follow-Up Study

http://dx.doi.org/10.5772/57461

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The participating adults with Down syndrome were recruited to the study at a specialized service centre for people with intellectual disabilities serving a population of 79 690 (December 2008), among them 723 people with identified intellectual disability. These include 84 people with Down syndrome; 19 of them were 0-19 years old, 65 were 20 years old or older. Forty of

Assessments of adaptive behaviour were conducted to 42 persons with Down syndrome (Table 1). Twenty five persons had repeated assessments. These persons' proxies had noticed a change of mood, behaviour or performance. At the time of the first evaluation, their age range was 24-61 years, with a mean of 45.8 and SD of +/- 8.4; at the time of the last evaluation, the corresponding figures were 25-65.5, 48.8, and +/- 8.4 years, respectively. The mean time of follow-up was, thus, 3.0 years (range 0-8 years). Five participants died during the follow up. Twenty participants (80%) of the 25 were 40 years or older at the time of the first evaluation. Most participants (17/25, 68%) resided at the beginning of the follow-up in small group homes, seven (28%) at home with parents or siblings and one in institution. Fourteen participants (56%) had organized weekly activities outside the home and two participants had part time sup‐

Repeated informant evaluations regarding observed changes in behaviour were recorded prospectively. Evaluations of adults with Down syndrome were performed over ten years, beginning in 2001. Adaptive behaviour assessments were performed by the closest relatives or carers who lived or worked with the participants and knew the persons and their daily skills

The current coping skills for daily living were assessed using the Adaptive Behavior Scale - Residential and Community, ABS-RC: 2 1993, Part I (Nihira *et al.* 1993). The Adaptive Behavior Scale (ABS) was chosen because the reliability and validity of this method are well established. Earlier research supports its feasibility in the use of scientific studies of ageing and dementia in people with intellectual disabilities (Rasmussen & Sobsey 1994; Prasher *et al.* 1998; Zigman

The first part of ABS is focused on personal independence and includes ten domains or subscales: Independent Functioning, Physical Development, Economic Activity, Language

the 65 adults belonged to the age group 40 years old or older.

and help in follow-up.

**2. Methods**

*Study population*

ported work.

for a long time.

*et al.* 2002).

*Methods*

Identification of persons with risk of early dementia remains a challenge (Shulz *et al.* 2004). Direct assessments of cognitive functions of people with intellectual disabilities may be difficult (Pyo *et al.* 2007). Informant-based assessments are useful as complementary or alternative methods in clinical work (Ball *et al.* 2004; Prasher *et al.* 2004; Niuwenhuis-Mark 2009).

The Adaptive Behavior Scale - Residential and Community (Nihira *et al.* 1993) and its earlier versions have been widely used in research. Cross-sectional studies have demonstrated lower scores on people with Down syndrome older than 40 years compared to younger participants with Down syndrome (Collacott 1992). The age-related decline of adaptive behaviour asso‐ ciates to dementia (Prasher & Chung 1996). Prospective studies have confirmed changes in adaptive behaviour (Rasmussen & Sobsey 1994; Prasher *et al.* 1998). Zigman *et al.* (2002) described the incidence and temporal patterns of adaptive behaviour changes in adults with intellectual disabilities. Rasmussen and Sobsey (1994) found stability of adaptive behaviour in adults with Down syndrome in the age groups younger than 40 years and a pattern of decline in self-help and communication skills in several individuals with Down syndrome older than 40, including declines in dressing, receptive language, vocational and domestic behaviour.

Relative preservation of cognitive and functional ability in persons with Down syndrome older than 45 associates with better survival whereas clinically, the most important disorders that are related to mortality are dementia, mobility restrictions, visual impairment, and epilepsy (Coppus *et al.* 2008).

Health co-morbidities in ageing persons with Down syndrome and Alzheimer's dementia are common (McCarron *et al.* 2005). Depression often precedes the onset of dementia in people with Down syndrome (Burt *et al.* 1992). Visual impairment and hearing loss are very common in elderly people with Down syndrome (van Splunder *et al.* 2006; Meuwese-Jongejeugd *et al.* 2006; Meuwese-Jongejeugd *et al.* 2008). Epilepsy is often seen at the same age with dementia (Collacott 1993). Hypothyroidism may also affect adaptive behaviour (Bhaumik *et al.* 1991). The absence of a medical illness predicts a higher level of adaptive behaviour, while dementia is a predictive factor for increased maladaptive behaviour (Prasher & Chung 1996) and psychiatric symptoms (Urv *et al.* 2010)

Medication for Alzheimer's disease might benefit many people with Down syndrome by slowing the progression of the disease (Prasher *et al.* 2002). Accurate measures are important for the follow-up and evaluation of treatments. It is necessary to find and use valid, reliable and sensitive methods for assessments of adults and ageing people with Down syndrome and Alzheimer's disease.

The aim of the present study was to explore the clinical usefulness of repeated assessments of adaptive behaviour in people with Down syndrome and suspected or confirmed dementia. Repeated assessments of adaptive behaviour in people at risk of functional decline might help to confirm the change and lead to necessary additional evaluations of the underlying reasons and help in follow-up.
