Bernice Seyfort, Ph.D.
Premature aging and early onset of dementia are well known characteristics of Down Syndrome (DS). The diagnosis of dementia can present a number of challenges to the clinician, in part because of the overlap with other syndrome-related conditions such as sensory losses (visual and hearing), hypothyroidism, and depression. (Haller, 2000) There is the further problem regarding accurate measurement tools. Although there are many scales and questionnaires designed to measure dementia onset (some specifically to be used on persons with DS), there does not appear to be one which is considered a gold standard (Pary, 2002). Direct neuropsychological measures of memory and attention are of limited use without premorbid assessments and appropriate norms.
Over the past six to eight years, persons with DS have been referred to the Island Mental Health Support Team, a multidisciplinary team serving Vancouver Island and the Sunshine Coast, for dementia screening. Typically, referrals have been made as people enter their fourth and fifth decade of life and begin to show signs of impaired social adaptive skills, memory failure and general slowing. Many of these clients also present with mood disorders and/or other mental health issues which overlap the picture of cognitive decline.
In l998 the author, along with team psychiatrist Dr Caron Byrne, presented initial findings from data gathered from a subgroup of persons with DS and depression to the National Association for the Dually Diagnosed (NADD) conference in Albuquerque, New Mexico. A synopsis of this presentation was published in the NADD Bulletin (Byrne & Seyfort, 1998). Findings suggested a high incidence of depression and hypothyroidism in persons with DS along with health problems disproportionate to the age of the individuals. A high incidence of premature aging and early onset dementia was also noted, mostly in those over the age of fifty. Persons with DS appeared to be at risk for depression precipitated by life events, some of a perceived minor nature. In brief, this initial study revealed unfolding risk factors in aging adults with DS. The results were interpreted within the limitations of a clinic and referred-base group of individuals. They were, however, consistent with findings reported in the research literature which included a number of longitudinal studies in Britain and the U.S. (Prasher, l995 & 1996; Collacott, l992).
The purpose of the current study is to present the progress and characteristics of aging in a group of persons with Down Syndrome in their fourth, fifth, and sixth decades of life. All individuals were from various communities on Vancouver Island and the Sunshine Coast, British Columbia, Canada.
Clinical Issues Relating to Aging and DS
Down Syndrome, which is associated with trisomy of the 21st chromosome, occurs in approximately 1 in 800 to 1000 live births. Over the past three or four decades, individuals with this condition are retaining a relatively good quality of life and are living into their fourth, fifth ,and sixth decade of life with a small number living longer.
Persons with DS reveal a characteristic cognitive profile on psychometric testing, especially in late adolescence or early adulthood. They typically demonstrate relative strength in the areas of social adaptive functioning along with strong learning capacity through observation, demonstration and other visual means. Language abilities, both receptive and expressive are often a relative weakness, particularly the former, and most noticeable for lengthy and grammatically complex instructions. Memory is a strength for well learned information and tasks. This pattern is observed to be relatively consistent across the range of mild to moderate developmental disabilities in persons with DS.
Numerous studies have demonstrated other unique syndrome-related features, including a high incidence of depression; reported in some studies to be three times as common in persons with DS compared with those with developmental disabilities due to other causes. Among persons with DS, initial onset of depression is typically seen in the early third decade of life (Kahn, Osinowo, & Pary, 2002).
Hypothyroidism is also frequently observed among persons with DS, ranging from 10 % to 30 % of individuals tested, depending on the particular research study (Chase, Osinowo, & Pary, 2002). Early onset dementia (typically becoming evident in the early fifties) is a noted characteristic in persons with DS and has been well investigated by longitudinal studies in recent years (Pary, 2002). The onset of dementia of the Alzheimer variety is presumed to be associated with metabolism of the protein amyloid and formation of plaques in the brain (Tomkowiak & Pary, 1995). Genes for the amyloid precursor protein (APP) have been located on the 21st chromosome (trisomic for persons with DS).
DS syndrome is associated with a high incidence of hearing problems both conductive and sensorineural. Studies suggest that 60% of adults with DS display some degree of hearing loss. Similarly, visual impairments are disproportionately associated with DS due to myopia, cataracts, strabismus and other less common visual anomalies such as keratoconus (Chase et al., 2002).
Individuals with DS are at risk for certain medical conditions such as gout and degenerative arthritis. Congenital heart malformations as well as acquired heart disease in later life are disproportionately seen in persons with DS as are certain types of leukemia (Hill et al., 2003).
The current study investigated 29 persons (17 females and 12 males) with DS who had been followed for a mean length of four years (range one to 10 years). Eight of the individuals were deceased at the time of this synopsis. The mean age of those living at the time of data gathering was 54.5 years while the mean age of death for the deceased subset was 57 years. All but three participants had received psychometric assessments some years before the study, thus representing presumed optimal functioning. The majority, 70%, tested in the moderate range of developmental disabilities, 20% in the severe and 10% in the mild range.
The protocol developed for assessing persons with Down syndrome suspected of early dementia onset includes the following:
1.The Down Syndrome Dementia Scale (Gedye, 1995), elaborated in reports to reflect increasing severity of positive symptoms over testing periods. On retesting, an emphasis was placed on employing the same respondents to increase reliability. This was usually possible due to the stability of families, propriety caregivers and group home staff in this geographical area.
2.A meeting with the client (sometimes in workshop settings which allowed for informal interaction), focusing on ease of engagement, ability to use language, attention and answers to questions of immediate and long term memory.
3.A clinical interview with caregivers and family members using a questionnaire designed to assess status of the following domains: Health (including medications, thyroid screening, other medical procedures, and recent visual as well as auditory screening), mood and behavior, communication, memory and attention, mobility, activities of daily living and socialization, and day program concerns as well as family observations.
4.A review of historical information; medical and psychiatric reports, social histories, past psychological tests (evidence of optimal functioning), early life experiences, and schooling. Historical files have been easily accessed for most individuals in this region.
All evaluations were completed by the author.
Summary of Findings and Conclusions:
The findings gathered on the 29 persons with DS, ranging in age from 44 to 66 years are presented in Table 1. They are in general agreement with studies carried out in North America and Europe. Genetic vulnerability to early aging and dementia is evident whether compared with others with developmental disabilities from non DS causes or with the general population at large. The early onset of dementia for most of the individuals described in this study was gradual, with initial signs of premature aging such as motor slowing, reduced language skills and deterioration of social adaptive abilities. A need for greater prompting to sustain a sequence of steps in familiar, routine tasks was one of the signs which revealed the passage from premature aging to a clearer picture of early dementia. Increased ritualistic behavior (commonly observed with DS) was also noted as dementia progressed, along with diminished ability to lay down and retrieve recent, or short term memories, with some retention of long term memories. A deterioration of executive functioning, e.g. the ability to start a familiar task independently and to stop when completed, as well as the ability to turn a verbal request into an action without motor prompts, became evident in the middle stages of dementia. A weakening of spatial orientation (getting lost in familiar environments) was also commonly reported by caregivers. Emotional disinhibition was noted as dementia progressed and was characterized by resistance to participating in social events, particularly where the environment was complex (crowded and noisy). The inability for new learning to occur also made new settings and unfamiliar people especially hard to deal with for the individual as dementia progressed.
Depression, while typically occurring in the third decade of life for persons with DS was also noted in some cases to occur later and precede or overlap the onset of dementia. The sudden occurrence of dementia, often earlier than the fifth decade, was associated (in a small number of cases) with signs of a mood disorder complicated by hallucinations and delusional thoughts. The high incidence of depression noted in this study (51%) reflects the referral bias of a clinic population served by a team which includes psychiatric consultation. All persons diagnosed with depression were seen by team psychiatrists and treated pharmacologically (usually with an SSRI). Although medication ameliorated mood problems and thus contributed to improved quality of life, day to day cognitive functioning generally did not return to premorbid levels for those in their fourth, fifth or sixth decade of life.
The high incidence of thyroid dysfunction observed in this group of persons with DS appears excessive compared to other studies. This is possibly due to the advanced age of participants, some of whom were not diagnosed until their fourth decade of life. All person diagnosed with hypothyroidism were being treated pharmacologically by their general practitioner.
The relatively high incidence of sensory impairments in this population of persons with DS presents a formidable challenge when assessing for dementia.
Both visual and auditory deficits tend to socially isolate an individual. Those with hearing impairments in particular tend to be less engaged through language. Hearing aides are often poorly tolerated by people with disabilities when offered late in life. Visual defects, by comparison, are more likely to be corrected with lenses or, in the case of cataracts, laser surgery. The present study did not include any persons with total impairment in the visual or auditory modality.
The issue of chronic illness was markedly apparent in this aging population. Gout, bronchial disease, arthritic deterioration of joints and heart problems were common as was excessive weight gain. The cycle of weight gain, joint deterioration and resistance to exercising was further noted.
In summary, the information gathered from this small group of persons aging with DS stresses a need for medical, social and behavioral support within communities where people reside. Education of physicians, caregivers and family members is crucial to understanding the aging process in persons with DS. This geographical area offers the services of a professional team with specialized knowledge in the diagnosis and treatment of conditions afflicting persons with developmental disabilities and is readily available to communities on Vancouver Island and the Sunshine Coast.
Adequate screening for high risk ailments such as sensory deficits, mood disorders, and thyroid dysfunction is important to the early diagnosis and treatment of these conditions. The use of anticholinesterase inhibitors (e.g. Aricept) as a method of slowing the pace of dementia in persons with DS is now receiving considerable attention and has been cautiously supported by some clinicians (Prasher, Huxley, & Haque, 2002). This form of treatment is, however, still being investigated.
From a psychosocial perspective, individuals with dementia benefit from a stable, caring home environment with familiar caregivers. Simplifying expectations and providing sufficient assistance is necessary while maintaining sufficient stimulation and exercise to promote optimal functioning and sustain quality of life.
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For further information:
Bernice Seyfort, Ph.D.
Island Mental Health
Vancouver, BC, Canada