Dementia

Dementia is defined as a gradual alteration in mental and cognitive capabilities. It can manifest in the form of language, memory or behavioral changes signaling a decline from the previous level of function.

Incidence

• The prevalence of dementia in the population greatly increases with age. While only 1% of the population experiences dementia by age 60, by age 85 at least 50% of the population is affected.
• Currently, an estimated 1.5 million people have severe dementia and an additional 1-5 million persons have mild to moderate dementia .
• The majority of dementia cases, 60-70%, are attributed to Alzheimers disease (AD).
• The second most common form is vascular dementia, which accounts for 10-20% of dementia patients .
• Less common causes of dementia include Lewy body dementia, Pick's disease, Creutzfeldt-Jakob disease, hydrocephalus, Parkinson's disease, brain tumors, and metabolic disorders.

Type of Deficit	Common Presentations
Cognitive	Impairments in language, praxis, judgment, visuospatial function, related mental activities
Extrapyramidal	Rigidity, bradykinesia, movement disorders, abnormalities of gait
Functional	Loss of ability to perform personal care tasks, changes in social functioning
Neurologic	Visual field deficits, hemiparesis, hemisensory loss, asymmetric deep tendon reflexes, unilateral extensor plantar response
Personality	Indifference, regression, impulsiveness

Clinical Presentations

• Dementia is characterized by gradual and progressive memory impairment.
• Memory loss, naming problems, forgetting items, and visuospatial confusion characterize the early stage of dementia.
• The middle stage is characterized by loss of reading ability, decreased performance in social situations, increased difficulty in finding words and names, intermittent disorientation to time, inability to recognize familiar persons, behavioral problems, and losing directions.
• Late-stage symptoms include extreme disorientation, inability to dress and perform self-care, increasing delusions, hallucinations, and progressive loss of other activities of daily living and personality change.
• Rapid deterioration of mildly demented individuals is sometimes prompted by urinary tract infection, congestive heart failure, hypothyroidism, or delirium.
• Emergency treatment of dementia may be necessary if aggression, psychosis, or activity disturbances are present.
• Risk factors for dementia include advanced age, family history, and abnormal apolipoprotein status.

Diagnostic Evaluation

• Generally, patients should be evaluated for dementia if any of the following are present:
  • Memory or cognitive complaints with or without functional impairment
  • Questions of competency in elderly patients
  • Depression or anxiety in patients with cognitive complaints, or physician suspicion of cognitive impairment during a clinical interview.
• If suspicion of dementia exists, reversible causes such as subdural hematoma, normal pressure hydrocephalus, hypothyroidism, and the dementia syndrome Serotonin syndrome of depression must be eliminated to make a definitive diagnosis.
• Lab tests commonly used in the assessment of dementia include complete blood count, serum electrolytes, calcium, glucose, BUN, creatinine, liver function tests, serum B12,

  Table: Diagnostic criteria of dementia according to WHO

  Diagnostic Criteria for Dementia Decline in verbal and nonverbal memory, significant decrease in ability to learn new information, present for at least 6 mo Decrease from premorbid levels in cognitive abilities such as planning and organizing and general processing of information Preserved awareness of environment, delirium is absent Decline in emotional control or motivation or a change in social behavior

  Table: DSM IV diagnostic criteria for AD

  Diagnostic Criteria for AD Development of multiple cognitive deficits manifested by memory impairment and one or more of the following: aphasia, apraxia, agnosia, disturbance in executive functioning Cognitive deficits cause a reduction in functioning from premorbid state Course is characterized by gradual onset and progressive cognitive decline Cognitive deficits are not caused by other central nervous system disturbances that lead to memory and cognition deficits or systemic conditions known to cause dementia Deficits do not occur exclusively during delirium Disturbance not better accounted for by an axis 1 disorder

  and serology for syphilis. In some cases sedimentation rate, serum folate level, HIV testing, chest X-ray, and urinalysis should be performed.

• Mental status tests examine orientation, recent and remote memory, language, praxis, visuospatial relations, calculations, and judgment.
• Neuroimaging is helpful in identifying potentially treatable conditions that can otherwise be missed such as tumors, subdural hematoma, hydrocephalus, and strokes.
• Neuropsychological testing is commonly used in cases of borderline or suspicious dementia.
• Cognitive screening should examine memory, ability to calculate language, visuospatial skills, and degree of alertness. The MMSE is commonly used to detect cognitive impairment.
• Scanning techniques such as PET and SPECT examine cerebral function.
• EEG is not routinely performed, but it can be used to identify toxic or metabolic disorders, partial complex seizures, or Creutzfeldt-Jakob disease.

Alzheimer's Disease (AD)

• The onset of AD is characterized by the impairment of memory and orientation, while speech and motor abilities are preserved.
• Other clinical features include depression, anxiety, behavioral disorders and speech difficulties.
• The ability to perform everyday activities may be hampered by impaired visuospatial processing.
• In the early stages of AD most neurologic and extrapyramidal functions are preserved in typical forms of the disease.
• Once a positive diagnosis of AD can be made, survival ranges from 8-10 yr.

Vascular Dementia

• The symptoms of vascular dementia largely parallel those of AD. However, diagnosis requires not only cognitive dysfunction, but also signs of cerebrovascular disease upon neurologic exam.
• Common physical findings include exaggerated or asymmetric deep tendon reflexes, gait abnormalities, weakness of an extremity, hemiparesis, a unilateral extensor plantar response, or visual field deficits.
• The presence of extrapyramidal signs in conjunction with gait abnormalities indicates Parkinsonism, progressive supranuclear palsy, or AD.

Frontal Lobe Dementia

• Pick's disease often presents with language impairments such as logorrhea, echolalia, and palilalia. Behavioral impairments are often present as well.

  Table: Diagnostic criteria for vascular dementia according to WHO

  Diagnostic Criteria for Vascular Dementia Dementia of a specified level of severity Unequal distribution of deficits in cognitive function If focal damage is evident it will manifest as one of the following: unilateral spastic weakness of limbs, unilateral increased tendon reflexes, an extensor plantar response, and pseudobulbar palsy History, examination, or tests disclose severe cerebrovascular disease which may be judged to be related to the dementia

• Creutzfeldt-Jakob disease is a rare, rapidly progressing form of dementia. It generally presents with vague initial symptoms such as irritability and somatic sensations. Motor signs like myoclonus, Parkinsonism, and motor neuron dysfunction may also be present.
• Normal pressure hydrocephalus is a poorly understood cause of dementia characterized by a triad of gait disorder, urinary incontinence, and cognitive decline.

Treatment

• Nonpharmacologic treatment is often employed for certain manifestations of dementia such as circadian rhythm disturbances, catastrophic reactions, and wandering.
• Pharmacologic treatment becomes necessary when agitation, physical outbursts, or significant delusions or hallucinations are present.
  • Antipsychotics are generally effective for psychotic symptoms and nonpsychotic agitated behavior.
  • Stronger neuroleptics like haloperidol have better side effect profiles than low potency agents such as thioridazine and chlorpromazine.
  • Benzodiazepines can be used if neuroleptics are contraindicated. It is generally best to use short-acting agents like lorazepam, temazepam, and oxazepam.

Alzheimer's Disease

• Acetylcholinesterase inhibitors are commonly used to slow the breakdown of acetylcholine, an essential neurotransmitter in cognitive functioning. These drugs have not proven to stop or reverse the progression of AD.
• The two most commonly prescribed drugs for AD are donepezil and tacrine.
  • Donepezil is regarded as the first-line treatment for dementia as it is more selective, longer-acting, and has fewer side effects than tacrine.
  • Tacrine is commonly prescribed as an alternative to donepezil. However, up to 20% of patients cannot tolerate tacrine's cholinergic side effects.
  • Other AChE inhibitors that have shown efficacy but have not yet been approved in the United States include rivastigmine, metrifonate, and galantamine.
• Besides AChE inhibitors there are alternative treatments that are sometimes used for the treatment of AD. Commonly prescribed agents include:
  • Ibuprofen (400 mg, 2-3 times/day)
  • Vitamin E (800-2000 IU/day)
  • Conjugated estrogens. Estrogen shows promise as a treatment for cognition, mood, behavior, and motor disturbances associated with dementia.
  • Another class of drugs that has been examined is anti-inflammatory drugs. Anti-inflammatory drugs change the cerebral inflammatory response to amyloid protein deposits, thereby reducing the risk of developing AD or slowing the progression of symptoms.

Table: Nonpharmacologic interventions for dementia

Presentation	Intervention
Verbal outbursts/ mild delusions	Reassurance Ignoring behavior Diversionary strategies
Circadian rhythm disturbance	Avoid night time fluids Treatment of painful conditions that may be disrupting sleep Encourage daytime exercise Discourage daytime napping
Catastrophic reactions	Approach patient in calm manner Avoid excessive external stimuli Limit demands

Vascular Dementia

• The treatment of vascular dementia is focused on the treatment of risk factors. As hypertension is one of the more common risk factors for vascular dementia, antihypertensive drugs are commonly prescribed.
• Systolic blood pressure should be kept below 150-160 mm Hg and diastolic blood pressure should be in the range of 85-95 mm Hg. Because of cerebral artherosclerosis, treatment that lowers diastolic blood pressure below 85-95 mm Hg may worsen cognitive impairment.
• Enteric-coated aspirin is sometimes prescribed in the range of 81-325 mg daily.
• Vitamin E, 800-2000 IU daily, is also prescribed in some cases.