Abnormal Psychology

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The Nature of Psychopathology and Abnormal Psychology
The Diagnosis of Mental Disorders

Dementia of the Alzheimer's Type (294.1x)

DSM-IV-TR criteria

  • A. The development of multiple cognitive deficits manifested by both

    • 1) memory impairment (impaired ability to learn new information or to recall previously learned information) and
    • 2) one (or more) of the following cognitive disturbances:

      • a) aphasia (language disturbance)
      • b) apraxia (impaired ability to carry out motor activities despite intact motor function)
      • c) agnosia (failure to recognize or identify objects despite intact sensory function)
      • d) disturbance in executive functioning (i.e. planning, organizing, sequencing, abstracting)




  • B. The cognitive deficits in Criterion A1 and A2 each cause significant impairment in social or occupational functioning and represent a significant decline from a previous level of functioning.
  • C. The course if characterized by gradual onset and continuing cognitive decline.
  • D. The cognitive deficits in Criteria A1 and A2 are not due to any of the following:

    • 1) other central nervous system conditions that cause progressive deficits in memory and cognition (e.g., cerebrovascular disease, Parkinson's disease, Huntington's disease, subdural hematoma, normal-pressure dydrocephalus, brain tumor)
    • 2) systemic conditions that are known to cause dementia (e.g., hypothyroidism, vitamin B12 or folic acid deficiency, niacin deficiency, hypercalcemia, neurosyphilis, HIV infection)
    • 3) substance-induced conditions


  • E. The deficits do not occur exclusively during the course of a delirium
  • F. The disturbance is not better accounted for by another Axis I disorder (e.g., Major Depressive Disorder, Schizophrenia
  • *Code based on presence or absence of a clinically significant behavioral disturbance:

    • 294.10 Without Behavioral Disturbance: if the cognitive disturbance is not accompanied by any clinically significant behavioral disturbance.




Associated Features

  • Individuals at risk and initial stages - Individuals with Down Syndrome and individuals with past head trauma are at a greater risk for developing Dementia of the Alzheimer's Type.
  • Physiological precursors of Alzheimer's may be seen as early as the 40s, though recognizable symptoms do not present until later in life.
  • Associated laboratory findings - Not widely accepted, sensitive, and specific biological marker is currently available that is universally accepted as diagnostic of Dementia of the Alzheimer's Type in a living individual. In the majority of cases, brain atrophy in Dementia of the Alzheimer's Type, with wider corticalsulci and larger cerebral ventricles than would be expected given the normal aging process. This may be demonstrated by computed tomography (CT) or magnetic resonance imaging (MRI). Microscopic examination usually reveals histopathological changes, including senile plaques, neurofibrillary tangles, granulovascular degeneration, neuronal loss, astrocytic gliosis, and amyloid angiopathy. Lewy bodies are sometimes seen in the cortical neurons.
  • Associated physical examination findings and general medical conditions - In the first years of illness, few motor and sensory signs are associated with Dementia of the Alzheimer's Type. Later in the course, myoclonus and gait disorder may appear.
  • Seizures occur in approximately 10% of individuals with the disorder


Gender and cultural differences in presentation

Alzheimer's is seen more in female patients than in males.

The onset of Alzheimer's before age 50 is rare in both sexes.

Epidemiology

The prevalence of Dementia of the Alzheimer's Type increases dramatically with increasing age, rising from 0.6% in males and 0.8% in females at age 65 (all levels of severity) to 11% in males and 14% in females at age 85.

At age 90 the prevalence rises to 21% in males and 25% in females, and by age 95 the prevalence is 36% in males and 41% in females.

Moderate to severe cases make up about 40%-60% of these estimated prevalence rates.

Etiology

Dementia of the Alzheimer's Type is chronic and degenerative.

In many cases, initial deficits in working memory are followed by aphasia, apraxia, and agnosia. Coinciding with these physiological changes are behavioral changes; individuals may become increasingly more irritable and, in some cases, territorial. Familiar surroundings will become unfamiliar; if home remodeling has been done in the past several years, individuals with Dementia of the Alzheimer's Type may begin to perceive their homes as more and more foreign.

In the more advanced stages, individuals will develop motor disturbances and will eventually may become fully incapacitated.

Average life expectancy from the onset of Dementia of the Alzheimer's Type to its conclusion in death is approximately 8-10 years.

Link to Diabetes - While research has failed to demonstrate conclusively any causal relationship between Dementia of the Alzheimer's Type and Diabetes, it is been established that Diabetes and Alzheimer's are highly correlated. Individuals with Diabetes are at a severe risk when comorbid Alzheimer's is present. Individuals with Diabetes often must have extremities amputated due to infection, and if said individuals have Alzheimer's and cannot remember that these extremities have been lost, there can be dire consequences (e.g. serious falls).

Empirically supported treatments

Supported treatments include caregiving and pharmacotherapy.

Links

  • There are many challenges for family members of Alzheimer's patients. Click here for one family's story: Challenges of Alzheimer's
  • Journal articles:

    • Do neuropsychological tests detect preclinical Alzheimer's Disease?
    • Relearning face-name associations in early Alzheimer's Disease




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