Alzheimer's disease and individuals with Down syndrome

Lisa R. Stanton and Rikus H. Coetzee

The clinical picture of Alzheimer's disease in Down's syndrome is complex, because of the pre-existing cognitive impairment and atypical presentation.  Difficulties making a diagnosis include "psychosocial masking", with refers to the limited social skills and lack of life experience that a person with a disability might exhibit.  Many individuals with disabilities may not present their symptoms verbally, because of limited communication skills resulting in the care-givers being most likely to notice a change.

Early onset symptoms vary from person to person, but the acquisition of deficits tend to mimic those seen in Alzheimer's disease generally.  Deterioration in memory, learning and orientation tend to be the first signs, and increased dependent.  Personality change including low mood, excessive over activity, restlessness, disturbed sleep, excessive uncooperativeness and auditory hallucinations occur.

It is important to differentiate age-related cognitive decline from early dementia. 

Symptoms:

Cognitive:  forgetfulness of recent events, geographical disorientation, loss of previously learned skills, and confusion.

Affective:  low mood, insomnia/hypersomnia, decreased concentration, aggression and irritability, anxiety and fearfulness, and loss of energy.

Behavioral:  increased dependence, social isolation, over activity, restlessness, uncooperativeness and personality change. 

Perceptual:  hallucinations in any modality

Neurological:  Dysphasia leading to Aphasia, apraxia, gait disturbance, seizures, urinary incontinence, dystonias and loss of mobility. 

Full psychiatric, personal, past medical and family histories are essential.  Attention should be paid to developmental, social and medication histories as well as interviews with care givers.  Some potential assessment batteries include:  The test for Severe Impairment (Albert & Cohen, 1992), the Spatial Recognition Span (Moss et al, 1986), The Dementia Scale for Down's syndrome (Gedye, 1995) and the Dementia Questionnaire for Persons with Mental Retardation (Evenhuis 1996).  For more information on test batteries see Burt & Aylward (2000) 

Adapted from Down's syndrome and dementia, Advances in Psychiatric Treatment (2004) 10: 50-58, 2004, The Royal College of Psychiatrists.  For Full article: http://apt.rcpsych.org/cgi/content/full/10/1/50