EARLY-ONSET ALZHEIMER’S DISEASE
Presenile dementia; Presenile Alzheimer’s disease; Young-onset Alzheimer’s disease; Familial AD; FAD; AD; EOAD
Early-onset Alzheimer’s Disease (AD) is the diagnosis of AD for a person younger than age 65 years, and accounts for approximately 5 to 10 percent of all cases of AD. AD is a degenerative, irreversible brain disease that usually affects older people and causes a dementia characterized by the gradual loss of previously attained cognitive abilities, such as memory, language, judgment, and the ability to function. Physiological changes in the brain include the rampant growth of two abnormal structures, amyloid plaques and neurofibrillary tangles, which interrupt normal brain activity. The onset of AD is subtle; memory impairment is frequently its earliest manifestation, quickly followed by learning and language impairments. Because people with early-onset AD are often in the work force, it is not uncommon for the disease to first manifest as a decline or loss in their ability to perform work-related activities. In the earlier stages of AD, depression is a common complaint. In later stages, agitation, changes in personality and behavior, restlessness, and withdrawal become evident. People with early onset AD decline possibly at a faster rate than those with late onset AD.
TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
The diagnosis of early-onset AD is based on the combination of clinical and family history; neurological, cognitive, or neuropsychological examination; and neuroimaging. Pertinent clinical information includes history of onset and description of cognitive and functional impairments at home and at work. Currently, there is no specific clinical or laboratory diagnostic test for early-onset (or late-onset) AD and at present, the diagnosis can only be confirmed by brain biopsy or postmortem examination of the brain. A decline in Mini-Mental Status Examination (MMSE) scores over time is a likely indicator of possible dementia. Neuroimaging, such as computerized tomography (CT) or magnetic resonance imaging (MRI) is useful to demonstrate changes in the brain and to exclude other causes of dementia.
ICD-9: 290.0, 290.1, 290.10, 290.11, 290.12, 290.13, 294.1 and 331.0
ONSET AND PROGRESSION
People diagnosed with early-onset AD experience gradual cognitive decline until death. Death usually results from pneumonia, malnutrition, or general body wasting. The average time of survival after diagnosis of early-onset AD varies but generally is 8 to 10 years, and many people with early-onset AD require institutionalization.
Currently there is no treatment to cure or slow the progression of early-onset AD. Treatment for the symptoms of early-onset AD may include drugs such as cholinesterase inhibitors (galantamine, rivastigmine, or donepezil) and an N-methyl D-aspartate (NMDA) antagonist (memantine).
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for Evaluation:
Clinical information documenting a progressive dementia is critical and required for disability evaluation of early-onset AD. The preferable source of this information is the clinical records from the claimant’s medical source(s).
Activities of daily living report or a similar report completed by relative or caregiver.
Documentation of dementia by standardized testing such as the Clinical Dementia Rating (CDR) scale with a score of = 1, MMSE with a score of = 24, or equivalent test is helpful but not required.