Health Care for People with Intellectual and Developmental Disabilities across the Lifespan
Chapter 116 - Dementia: Screening, Evaluation, Diagnosis and Management – Seth M.
Keller, Matthew P. Janicki, and Lucille Esralew
https://ebookcentral.proquest.com/lib/rug/reader.action?docID=4514222
Abstract
The emergent acknowledgement of the increase rate of dementia among adults with intellectual and
developmental disability (IDD) has led to the recognition of a lifespan approach to securing and
providing services with relevant supports. Consideration of what is most needed in older age has
taken on more prominence. Service organizations are responding to the emergence of age-
associated neuropathologies as coincident to lifelong conditions and are attempting to adapt their
services for continued community care until death. The historical focus on aging among adults with
IDD and the recent focus on dementia has heightened awareness of the latter age needs of adults
with IDD – and in particular those at-risk of or already affected by dementia. The positive outcome of
these public health initiatives is that more dementia-capable services are being developed,
technologies are improving, and there is an increased interest in maintaining quality of life through
to the end-of-life, irrespective of the nature and complexity of conditions prevalent in older age.
Introduction
Adults with intellectual and developmental disabilities (IDD) are living longer and consequently some
age-associated decline in function is common; however to differentiate between normative cognitive
aging, and age-associated pathology in this group (such as dementia) can present a challenge. In this
chapter we focus primarily on intellectual disability, as dementia is more prevalent in this group.
Intellectual disability is a term encompassing those conditions that are characterized by below
normative intellectual functioning, are due to cognitive impairment (organic or functional) present
since birth, infancy or manifest within the developmental period, are not attributable to mental
illness or psychiatric impairment or late life cognitive impairment (e.g., dementia), and generally vary
in degree and co-impairments.
Generally, intellectual disability is defined as a condition affecting persons who (a) have intellectual
limitations that significantly limit their ability to successfully participate in normal day- to- day
activities such as self-care, communication, or work, (b) have developed the intellectual limitation
during the ‘developmental period’, and (c) have a limitation that is anticipated to result in long term
adaptive or functional support needs.
IDD can be constructively compensated by training, education, remediation, habilitation, and
supports for life activities and accommodated through environmental and programmatic supports.
Knowing an individual’s prior baseline level of cognitive and general physical function is key to
determining if his or her current status is the same, fluctuating, or declining.
The prevalence of dementia among adults with IDD has been shown to be generally the same as that
of the general population, with the exception for adults with Down syndrome, where the rate is
much higher. Among adults with IDD, Alzheimer’s type dementia (DAT) is more prevalent in adults
with DS, while there is a range of dementias prevalent in adults with other etiologies of IDD. Notable
onset among adults with IDD generally occurs in the early 50s for adults with DS and the late 60s for
others. Some changes may begin to occur earlier. While dementia symptoms in people with IDD
,generally follow the patterns observed in the general population, early suspicions are generally
triggered by noticeable personality changes in adults with DS and notable memory loss in adults with
other etiologies of IDD. Trajectories and duration of decline in adults with IDD generally mirror those
of the general population, but duration among adults with Down syndrome is briefer – usually
between 2 and 7 years and the trajectories more notable. In some adults with DS, aggressive forms
of AD can lead to early death generally within 2 years of onset.
One notable difference is the occurrence of late onset seizures which are found to a large extent in
adults with DS, while seemingly less in the general population. Falling and gait dysfunction may
discriminate among the various dementia subtypes.
Screening, Assessment and Diagnosis
Early detection in important to noting changes in behavior, identifying conditions that affect function
and behavior, and sorting out those conditions amenable to medications or other treatment (e.g.,
endocrine and psychiatric disorders and adverse medication reactions) from those that are related to
brain disease. Early detection enables an early start with treatment and interventions and helps lead
to eventual diagnosis.
There are challenges to arriving at an accurate diagnosis, as individuals with IDD may not be able to
report or maybe even appreciate early symptoms of dementia, and that functional changes may be
subtle and not easily observed. Early diagnosis is also hampered because commonly used dementia
assessment tools are not relevant for people with IDD and it may be diffi cult to measure change
from baseline levels of functioning. Further, various behaviors and changes in function may be
mistakenly attributed to the individuals’ underlying IDD, an error in clinical diagnostic reasoning
termed “diagnostic overshadowing.”
To facilitate early detection, in the United States the National Task Group on Intellectual and
Developmental Disabilities and Dementia Practices (NTG) recommended using the NTG- Early
Detection Screen for Dementia (NTG- EDSD). The purpose of the NTG-EDSD is to offer family and paid
caregivers a means to record their observations regarding changes in areas of cognitive and adaptive
functioning known to be associated with dementia. he NTG-EDSD is not an instrument for the
diagnosis of dementia, but a tool that can document that an individual’s level of function has
changed from a prior level.
Making Determinations
After the history and associated background information has been collected and analyzed, brain
imaging and additional tests are required to exclude other causes that may explain the reason for the
decline in memory or function.
A simple medical office based test of cognitive dysfunction for a person with IDD does not exist. Best
practice assessment includes collateral information, informant ratings and direct clinical assessment.
To date, there is no consensus regarding a standardized battery to assess cognitive dysfunction in
persons with IDD.
Benefits of differentiating types of dementia as part of the diagnostic work-up include diagnostic
precision, potential medication treatment variations, estimating life expectancy, setting up care
, management plans on expected behavioral presentations and progression, communication and
interaction variations, and projecting expectations for change in care needs
Course of the Disease
Alzheimer’s disease is a progressive illness that will lead to loss of function, changes in behavior,
growing needs for caregiver support, gross debilitation, and eventual death. It would be best to
consider the type of care based on a stage-of- disease approach: early, mid-stage, late, and end-
stage. The entire duration of the disease may be as long as 10 or more years, but there have been a
number of cases in adults with Down syndrome who have had a rapid progression leading to death
only within 1–2 years.
Caregiver burden greatly increases as the disease progresses and potential “burnout” can occur
which can increase the chance for neglect and abuse. Dementia and its related cognitive and
challenging behaviors may become signifi cantly exaggerated at any time during the illness if an
environmental, social, or underlying health issue arises. If acute changes occur to the individual it is
imperative that the underlying cause for these changes be determined and rectif i ed if at all
possible. Crisis intervention including emergency department and hospital admission may be thus
avoided.
Pharmacologic Management
The mainstay of therapy is to provide cognitive enhancers which are meant to stabilize, improve, and
help slow the progression of Alzheimer’s disease. Cholinesterase inhibitors; Donepezil (Aricept),
Rivastigmine (Exelon), Galantamine (Razadyne) curb the breakdown of acetylcholine, a chemical in
the brain important for memory and learning. These types of medications help increase the levels of
acetylcholine in the brain. These drugs may slow the progression of symptoms for about half of
people taking them but only for a limited time, on average 6–12 months.
Memantine (Namenda) is approved to treat moderate-to-severe Alzheimer’s disease. Memantine
works by a different mechanism than other Alzheimer’s treatments; it is thought to play a protective
role in the brain by regulating the activity of a different brain chemical called glutamate. Glutamate
also plays a role in learning and memory. Brain cells in people with Alzheimer’s disease release too
much glutamate. Memantine helps regulate glutamate activity. The usefulness of Memantine with
persons with IDD is still in question.
While these medications have been tested on older adults without IDD, there have been no large
randomized controlled studies in adults with intellectual or developmental disabilities.
Non-Pharmacologic Management
Persons with IDD may display increased neurobehavioral signs of dementia including an increase in
impulsivity, reactivity to environment, and care handling techniques. As is true of older persons in
the general, adults with IDD may become more dependent upon others for care as they decline
cognitively and functionally; they may also have less coping skills to deal with feelings of anger, fear
and frustration that may accompany their experience of decline. Best practice in care management
