**2. Methods**

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

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

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

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

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

by the presence of Alzheimer's disease (Iacono *et al.* 2010).

314 Pharmacology and Nutritional Intervention in the Treatment of Disease

2009).

(Coppus *et al.* 2008).

Alzheimer's disease.

psychiatric symptoms (Urv *et al.* 2010)

#### *Study population*

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

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‐ ported work.

#### *Methods*

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 for a long time.

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 *et al.* 2002).

The first part of ABS is focused on personal independence and includes ten domains or subscales: Independent Functioning, Physical Development, Economic Activity, Language Development, Numbers and Time, Domestic Activity, Prevocational/Vocational Activity, Self-Direction, Responsibility and Socialization. The ABS Manual reports that factor analysis has found three Part One factors: Personal Self-Sufficiency, Community Self-Sufficiency, and Personal–Social Responsibility.

in the region gives prevalence's of dementia 38% (15 of 40 persons) in the age group 40 years and more, and 13% (two of 15 persons) in the age group 30-39 years. The prevalence estimate

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

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Of the 25 participants eleven (44%) had experienced long periods of depression. Thirteen (52%) had received antipsychotic medication mainly for behavioural problems, six of them already during early adulthood and eight for behavioural problems with dementia. Eleven persons were treated for hypothyroidism. Varying degrees of visual impairment were common, and three had cataracts. Recurrent faints were seen in eight, with falls causing fractures in three

Among participants with Alzheimer's disease (n=15), antipsychotic medication had been used for eleven (73%), depression had been diagnosed in ten (67%), thyroid disease in ten (67%), and epilepsy in seven (47%) participants. Among participants without Alzheimer's disease (n=10), antipsychotic medication had been used for two (20%), depression had been diagnosed in one (10%), thyroid disease in four (40%), and epilepsy in one participant (10%). Among eleven participants with depression (N=11), antipsychotic medication had been used for seven (64%), Alzheimer's disease had been diagnosed in ten (91%), thyroid disease in 6 (55%), and

A decline of daily functioning was observed by informants in regards to 19 of 25 persons, starting at the ages of 37-51 years with a mean of 44.9 and SD +/- 4 years in persons with full trisomy of chromosome 21. In addition, there was one participant with mosaic trisomy of

The mean ages, ABS total scores at first and last assessments and the calculated percentages of score changes per three years in subgroups of participants are presented in Table 1. The mean ABS total scores for the 25 participants with multiple assessments declined from 161 to 126 (21.8%) during the mean 3.0 years between the first and last assessments. The decline of ABS total scores associated very strongly to Alzheimer's disease: there was no decline in the mean ABS total scores in the group of participants with no suspected or confirmed Alzheimer's disease. The mean rates of ABS score change were higher in participant groups with Alzheim‐ er's disease (33.6% in three years), and depression (32.0%) compared to participants without these conditions (0.6% and 13.9% respectively). The participants treated with medication for Alzheimer's disease had lower mean rates of score declines compared to untreated patients, 31% and 40% declines in three years respectively. The mean rates of change were almost similar in groups of persons with and without epilepsy, antipsychotic medication, and hypothyroid‐

chromosome 21 whose decline started only at the age of 60 (Figure 3, participant 2).

of dementia for the age group 30 years and more is thus 31% (17 of 55 persons).

persons. Epilepsy was diagnosed in eight persons.

epilepsy in five (45%) participants.

*Adaptive Behavior Scale (ABS) scores*

*Informant observations*

ism. (Table 1)

*Medical problems*

Clinical evaluations were done by the principal investigator. These included interviews of the proxies, referrals for differential diagnostics and specialist consultations, and prescriptions and assessments of medications. Additional clinical data was drawn from the case records of the health centres, central hospital and service centre regarding all persons with Down syndrome in the region. The data of medical treatments for Alzheimer's disease, depression, behavioural problems, epilepsy, and other major health concerns possibly affecting adaptive behaviour were analyzed. The age at the time of the first observation of functional decline was calculated.

Informant ratings by ABS were scored and analysed. Total scores, scores for the ten subscales and three factors of ABS and changes of scores from the first to the last evaluation were counted. The ABS score changes as percentages per three years were calculated for subgroups of participants with and without Alzheimer's disease, depression, epilepsy, hypothyroidism, and antipsychotic medication use for challenging behaviour.

The ethical committee of the Kainuu Central Hospital approved the study and permission for combining data from medical and social records was given by the Ministry of Social and Health Affairs.
