Dementia and Intellectual Disability

Dr Roslyn Davis October 2010 Definitions

• Intellectual Disability: A disability that originates before theage of 18 and is characterised by significant limitations both in intellectual functioning and in adaptive behaviour as expressed in conceptual, social and adaptive skills. Diagnosis with I.Q. test plus evaluation of adaptive behaviour. • A lifelong condition of limited intellectual, social and vocational capabilities. May also have other sensory, psychiatric and physical disabilities depending on the cause. Levels of Intellectual Disability

• MILD: IQ 50-70. May read and write and function independently in many areas. • MODERATE: IQ 35-50 Have some word recognition only. Usually require support for daily living. • SEVERE: IQ 20-35 Have limited speech and may show ‘autistic’ features of behaviour and social interaction • PROFOUND IQ < 20 No verbal communication, limited recognition, fully dependent. • Overall prevalence in Australia-3% of population.= 588,700 in 2003. About 20% over 65 years old. Prevalence of Dementia in ID

• People with ID are living longer just as those in the general population • Population studies show prevalence of dementia is same as general population for those withoutDown’s syndrome • In Down’s syndrome prevalence is 25% for those over 40 years and 65% for those over 60 Dementia in Down’s Syndrome

• Have three copies of the gene on Chr 21 for production of APP • Most will show AD neuropathology after the age of 35 years • Average age of onset of clinical signs of AD- 50 years • Most studies ID group focused on Down’s syndrome Symptoms of Dementia in ID

• Loss of memory- both short and long term • Loss of skills in judgment and understanding • Change in adaptive behaviour-loss of skills in self care • Language difficulties- expressive and comprehension Clinical Course of AD in Down’s

• Memory impairment, temporal disorientation, reduced verbal output • In some the initial symptoms may be apathy and withdrawal • Later - loss of skills in ADL’s, gait becomes slow and shuffling • Onset of seizures in about 80% • Late stage - bedridden, incontinent, dysphagia, aphasia, rigidity Diagnosis of Dementia

• Standard tests like MMSE not useful • Require to show functional decline in 5 domains 1. Memory - most significant criteria 2. General mental functioning - thinking, planning 3. Higher cortical - dyspraxias, dysphasia, agnosia 4. Skills - living and working skills 5. Personality - disinhibitedbehaviours, apathy, stubborness, obsessiveness, rigidity Diagnosis of Dementia

• Informant assessment based on knowledge of previous level of abilities. • Changes should be progressive over time • Rule out delirium, depression, hypothyroidism and other medical or physical causes for the decline through full physical, psychological examination and appropriate pathology or radiology Diagnosis

• Depression can mimic dementia as in general population • In Down’s can be prodrometo onset of AD • In severe ID more difficult to diagnose - but progressive loss from baseline, apathy, loss of social interaction may present Diagnosis

• Informant questionnaires are available • ABDQ - VeePrasher(2004). 15 questions relating to the 5 domains. Cut-off scores for mild, moderate and severe AD • DMR- informant questionnaire • Short term memory • Long term memory • Spatial and temporal orientation • Speech • Practical skills • Mood • Activity and Interest • Behavioural disturbance Diagnosis

• DMR has different cut off scores for those with baseline mild, moderate or severe intellectual disability • Can use these as baseline levels to follow over time and show decline rather than scores being diagnostic Treatment

• Very limited evidence base to examine effectiveness of drug treatments. • Access issues due to PBS requirements • Non drug management includes correcting treatable factors eg. Hearing aids, glasses, mobility aids, environmental aids such as visual identifiers, visual timetables, managing challenging behaviours Case Study

• 58 year old female with Down’s syndrome • Moderate ID, previously independent ADLs, domestic skills, no literacy or numeracy • Deterioration over 12 months • Trialledon antidepressant but no change Case

• Short term memory loss - losing things, asking the same questions repeatedly • Unable to understand instructions as well • Loss of ability to shower and dress herself • Puts on clothes the wrong way • Less concerned about personal care • More obsessive and rigid • Now getting lost in familiar places Case

• Less aware of time • Loss of domestic skills • Gorging of food • Physical examination - no major abnormalities, pathology pending, needs hearing check. • ABDQ questionnaire-scored in the range for mild AD References

A.I.H.W (2008) Bulletin. Disability in Australia: Intellectual Disability Alzheimer's Disease International, Feb 2003. Dementia in Intellectual Disabilities Centre for Developmental Disability Studies. GP Guidelines- Health Care in people with Intellectual Disabilities Davidson P.W . Prasher V.P Janicki M.P (Ed) 2003. Mental Health, Intellectual Disabilities and the Aging Process. Blackwell Pub. Fraser W . Kerr M. (Ed) 2ndEd 2003. Seminars in The Psychiatry of Learning Disabilities. Gaskell. Troller J 2004 Treatment of Dementia in Individuals with Intellectual Disabilities