Dementia due to multiple etiologies; Vascular dementia Alzheimer’s disease (VaD); Parkinson’s dementia; Diffuse Lewy-Body dementia; Frontotemporal dementia (Pick’s disease); Huntington’s dementia; Prion dementia; Progressive Supranuclear Palsy (PSP)
Mixed Dementias are conditions with more than one etiology for the dementia. The combination of Vascular dementia and Alzheimer’s disease (VaD) is the most common form. The Vascular component is characterized by focal ischemic infarcts (strokes) and subcortical ischemic vascular disease, and has the potential to cause substantial focal neurological deficits such as aphasia, apraxia, or agnosia and motor manifestations such as paralysis, gait impairment, or Parkinsonian syndrome. The Alzheimer’s component is characterized by a progressive decline of memory and other cognitive abilities relative to a previous level of functioning. Mixed dementias are characterized by progressive and persistent intellectual decline compromising at least two spheres of cognition (i.e. memory, language, orientation, attention, executive abilities, etc). These individuals may also have motor and gait impairment, affective disturbances, sleep disturbances, and incontinence.
TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
The diagnoses of mixed dementias are based on a clinical history of cognitive decline, neurologic and cognitive/neuropsychologic examination, and neuroimaging. Pertinent clinical information includes history of onset and description of cognitive and functional impairments at home and at work. History of a previous stroke(s) adds to the likelihood of the diagnosis, but is not required. Currently, there is no specific clinical or laboratory test for the diagnosis of Alzheimer’s disease and its diagnosis can only be confirmed by brain biopsy or postmortem examination of the brain. Neuroimaging, i.e. computerized tomography (CT) or magnetic resonance imaging (MRI) is useful to demonstrate vascular lesions such as infarcts and lacunes, and to exclude other causes of dementia, some of which may be treatable.
ICD-9 Code: 290.4
ONSET AND PROGRESSION
Individuals diagnosed with mixed dementias experience a gradual, yet relentless, decline in cognitive functioning over a period of many years, approximately a decade. The vascular component of the disease may be marked, although not necessarily, by episodes of abrupt deterioration or shortening of the course of the disease.
Currently there is no treatment to cure or slow the progression of the Alzheimer’s component of mixed dementia. Treatment is therefore symptomatic and may include drugs that increase cholinergic transmission, antioxidants, glutamate receptor blockers, antipsychotics or neuroleptics, sedatives, and antidepressant and anxiolytic agents. Management of high blood pressure and other risk factors for cerebrovacular disease appears as a more effective approach to prevent brain infarcts and mixed dementias.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for Evaluation:
Clinical information documenting a progressive dementia is critical and required for disability evaluation of mixed dementias. The preferable sources of this information are the clinical records from the claimant’s medical source(s).
Documentation of dementia by standardized testing: Clinical Dementia Rating (CDR) scale with a score of =1, Mini-Mental State Examination (MMSE) with a score of = 20, or equivalent test is helpful but not required.
Activities of daily living report completed by relative or caretaker
Work activity or performance report completed by supervisor or co-worker
Neuroimaging studies, i.e., computerized tomography (CT) scan or magnetic resonance imaging (MRI) demonstrating brain infarcts, lacunae, or atrophy constitute helpful supportive evidence, but are not required