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Dementia

Thomas Horton

Background

  • Alzheimer’s Disease (AD): short-term memory deficits prominent
  • Vascular Dementia: “Stepwise decline” in memory and functional status
  • Lewy Body Dementia: hallucinations, memory difficulties with atypical Parkinsonism early
  • Frontotemporal Dementia: behavioral (aggressive or disinhibited), language (primary progressive aphasias) or memory (Alzheimer’s/FTD overlap) variants
  • Posterior Cortical Atrophy: visual difficulties and ocular apraxia preceding memory problems
  • Creutzfeldt-Jakob Disease (CJD): manifests with subacute cognitive decline, seizures, vision loss, personality changes. Can develop startle myoclonus
  • Corticobasal degeneration: focal neurologic changes with parkinsonism
  • Neurosyphilis: rare, but treatable, present with a range of cognitive changes. Develop meningovascular encephalitis. Pts can develop an arteritis, headache, and hydrocephalus.
  • Normal Pressure Hydrocephalus (NPH): “wet, wacky and wobbly” meaning incontinence, gait apraxia and cognitive changes (usually frontal symptoms)
  • Autoimmune Dementias: includes limbic encephalitis (like NMDA) where there are memory and personality changes, autonomic changes, hallucinations, and seizures
Normal Aging Mild Cognitive Impairment

Alzheimer’s Dementia

(DSM V Diagnostic Crit.)

Mild decline in working memory

More effort/time needed to recall new info

New learning slowed but well compensated by lists, calendars, etc.

+

No impairment in social & occupation functioning

Subjective complaint of cognitive decline in at least one domain

+

Cognitive decline is noticeable and measurable

+

No impairment in social & occupation functioning

Evidence of significant cognitive decline from a previous level of performance in one or more cognitive domains

+

Causes significant impairment in social & occupation functioning

+

Other medical & psychiatric conditions, including delirium, have been excluded

+

Insidious onset and gradual progression of impairment in at least two cognitive domains
Cognitive domains: learning/memory, language, executive function, complex attention, perceptual motor, social cognition
Alzheimer’s Disease Vascular Dementia Lewy Body Dementia Frontotemporal Dementia
Onset Gradual Sudden or stepwise Gradual Gradual (age < 60)
Cognitive Domains & Symptoms Memory, language, visuospatial Depends on location of ischemia Memory, visuospatial Executive dysfunction, personality changes, disinhibition, language, +/- memory
Motor Symptoms

Rare early

Apraxia later

 Correlates with ischemia Parkinsonism None
Progression Gradual (over 8-10 years) Gradual or stepwise with further ischemia Gradual, but faster than Alzheimer’s disease Gradual, but faster than Alzheimer’s disease
Imaging Possible global atrophy Cortical or subcortical on MRI Possible global atrophy Atrophy in frontal & temporal lobes

Evaluation

  • MINI-COG: Screening test for cognitive impairment (highly sensitive)
    • Ask pt to remember three words (banana, sunrise, chair). Ask pt to repeat immediately
    • Ask pt to draw clock. After numbers are on the face, ask pt to “set hands to 10 past 11”
      • Correct is all numbers in right position AND hands pointing to the 11 and the 2
  • Ask pt to recall the three words

MINI-COG Flowchart

MINI-COG Flowchart

  • MOCA: Montreal Cognitive Assessment

    • Lengthier test of cognition (but highly specific for cognitive impairment)
    • Useful for detecting subtle deficits as in Mild Cognitive Impairment (MCI)
    • Scores:
      • 18-25: Mild cognitive impairment
      • 10-17: Moderate cognitive impairment
      • <10: Severe cognitive impairment

  • Rule out reversible causes of dementia-like symptoms: DEMENTIA

    • Drugs
    • Emotional (depression)
    • Metabolic (CHF, COPD, CKD, OSA)
    • Endocrine (hypothyroidism, hyperparathyroidism, hyponatremia)
    • Nutrition (B12 deficiency)
    • Trauma (chronic SDH)
    • Infection
    • Arterial (vascular)
  • B12, thyroid studies
  • RPR, HIV testing in at-risk patient groups
  • Neuropsych testing can be done for more clear patterns of dysfunction
  • MRI brain with contrast if concerned for inflammatory or infectious causes
    • CJD: cortical ribboning on DWI with T2 hyperintensity in the thalamus and basal ganglia
    • Sulcal crowding and bowing of the corpus callosum can be seen in NPH on imaging

Management

  • Targeting Cognitive Impairment
    • Cholinesterase Inhibitors: Donepezil, rivastigmine
      • Indicated for any stage (except FTD)
      • SE: GI (nausea, diarrhea), bradycardia, orthostasis
    • NMDA antagonists: Memantine
      • Indicated in moderate to severe AD in combination with cholinesterase inhibitors
      • Fewer SE than cholinergic medications
  • Vitamin supplementation (i.e. Vitamin E)
    • Unclear benefit in delaying progression of dementia
  • Targeting Behaviors
    • Non-pharmacologic management has the best evidence of effectiveness
    • Depression: Treat with antidepressants (SSRI’s)
    • Sleep Disturbance: Mirtazapine (7.5 mg nightly) or Trazodone (25 mg nightly)
    • Agitation: Try SSRI (citalopram, sertraline)
      • Consider antipsychotics (black box warning increased risk of death in elderly)