Behavioral Symptoms of Dementia
Early Behavioral Changes Associated with
Alzheimer’s Disease in Down Syndrome
Changes in behavior and mood can be among the early signs of Alzheimer’s disease in adults with Down syndrome, sometimes emerging before dementia is clearly recognizable from memory or functional changes. Of particular importance are new or increasing anxiety, irritability, apathy or loss of initiative, disinhibition, agitation, restlessness or repetitive behavior, changes in eating or drinking, and altered sleep patterns. Changes in executive functioning—such as greater difficulty initiating activities, organizing behavior, or regulating emotions and impulses—may also accompany this early period.
Research suggests that apathy and other frontal-lobe or executive changes may be especially important during the prodromal or early stage of Alzheimer’s disease. Anxiety, irritability, depressive features, and sleep-related changes may also occur as dementia develops, although findings for depression have been less consistent. Activity levels can change in either direction: some people become unusually restless or agitated, while others become noticeably slower, less active, or less interested in previously enjoyed activities. Sleep disturbances are common in adults with Down syndrome both with and without dementia, so sleep problems alone do not indicate Alzheimer’s disease; nevertheless, they deserve attention because poor sleep may worsen cognitive and behavioral difficulties.
The most useful warning sign is a change from the person’s own longstanding pattern of behavior, rather than the presence of any one behavior. Persistent or progressive behavioral changes—particularly when they occur together with changes in memory, communication, social engagement, everyday skills, or independence—should prompt further assessment. Other possible causes, including pain, illness, medication effects, depression, sleep disorders, and environmental changes, should also be considered.
Recognizing these changes early is important not only for identifying possible cognitive decline but also for helping families and caregivers understand what may be happening and adapt support and treatment accordingly. Behavioral changes can increase caregiver burden and, as dementia progresses, may contribute to loss of stability in the person’s usual living situation. For this reason, systematic attention to behavioral change can be an important part of monitoring brain health and possible progression toward Alzheimer’s disease in adults with Down syndrome.
Sources: Dekker, A. D., et al. (2015). Behavioral and psychological symptoms of dementia in Down syndrome: Early indicators of clinical Alzheimer’s disease? Cortex, 75, 36–61. doi:10.1016/j.cortex.2015.07.032; Dekker, A. D., et al. (2021). The Behavioral and Psychological Symptoms of Dementia in Down Syndrome Scale (BPSD-DS II): Optimization and further validation. Journal of Alzheimer’s Disease, 81(4), 1505–1527.
Studies of Dementia Symptoms and Intellectual Disability
Bibliography version 12/15/2022
click on image to open PDF
Behavioral and Other Signs of Dementia in
Adults with Intellectual Disability
Look for change, describe the change, and track the change over time. A pattern of progressive change across behavior, cognition, communication, everyday functioning, or physical abilities provides much more useful information for assessment than any isolated behavior.
Dementia can occur in adults with intellectual disability who do not have Down syndrome, although the causes, age of onset, and pattern of symptoms vary considerably. As in other adults, Alzheimer disease may be responsible, but other forms and causes of dementia also occur. Because a person may already have lifelong limitations in memory, communication, reasoning, or everyday skills, the most important indication of possible dementia is usually a sustained change from that person's previous abilities and behavior rather than performance against population norms.
Early changes are not limited to forgetfulness. Families and support staff may first notice increasing difficulty completing familiar tasks, poorer attention or concentration, loss of previously established skills, greater confusion, changes in communication or language, reduced initiative, or difficulty organizing and carrying out activities. Behavioral changes can include new apathy or withdrawal, irritability, anxiety, depressed mood, agitation, restlessness, altered sleep, changes in eating, repetitive behavior, aggression, or other behavior that is unusual for the individual. As dementia progresses, changes may become apparent in self-care, continence, mobility, gait, eating and drinking, social engagement, and dependence on others for everyday activities. The particular pattern varies with the person, severity and cause of intellectual disability, and type of dementia.
No single behavioral change establishes that dementia is present. Pain, depression or anxiety, sensory impairment, sleep disorders, medication effects, seizures, infection or other illness, and changes in living or social circumstances can produce similar changes. A new behavior should therefore be treated as information to investigate, not automatically as a symptom of dementia. What becomes particularly concerning is a pattern of changes that persists or progresses and represents a clear departure from the person's established baseline.
Recording and Tracking Changes
For adults with ID, longitudinal observation is especially valuable. Family members and support staff who know the person well may notice changes that are not apparent during a brief medical appointment. Research also suggests that behavioral and functional changes can be harder for caregivers to recognize in people with more limited verbal abilities, making systematic observation particularly important.
Rather than simply recording that someone is "more confused," "aggressive," or "not himself," caregivers should document what has actually changed, when it began, how often it occurs, its severity, and whether it is affecting everyday functioning. It is also useful to record the circumstances surrounding a behavior—where and when it occurs, what happened beforehand, how the person responded, and whether there have been simultaneous changes in health, medication, sleep, staffing, residence, or daily routine. A simple dated log maintained over several weeks or months can reveal a pattern that might otherwise be missed.
Periodic use of an informant-based dementia screening instrument designed for adults with intellectual disability can provide a more structured record. Tools such as the NTG-Early Detection Screen for Dementia (NTG-EDSD), Dementia Questionnaire for People with Learning Disabilities (DLD), and Dementia Screening Questionnaire for Individuals with Intellectual Disabilities (DSQIID) are designed to capture change reported by someone familiar with the individual; such tools complement rather than replace clinical assessment. Reviews of ID-specific instruments particularly support informant-based approaches for following cognitive, behavioral, and functional change over time.