Dementia

Dementia

Background

  • Alzheimer’s Disease (AD): short-term memory deficits prominent
  • Frontotemporal Dementia: behavioral (aggressive or disinhibited), language (primary progressive aphasias) or memory (Alzheimer’s/FTD overlap) variants
  • Lewy Body Dementia: hallucinations, memory difficulties with atypical Parkinsonism early
  • 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 IV Diagnostic Crit.)

- Mild decline in 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 (Memory, executive function, language, or visuospatial perception)

+

- Cognitive decline is noticeable and measurable

+

- No impairment in social & occupation functioning

- Memory impairment

+

- Aphasia (language disturbance) OR

- Apraxia (impaired motor ability despite normal motor function) OR

- Agnosia (failure to recognize or identify objects despite intact sensory function OR

- Disturbed executive functioning

+

- Causes significant impairment in social & occupation functioning

+

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

 

 

 

 

 

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 draw hands to read 10 minutes after 11:00
      • 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

 

  • MOCA: Montreal Cognitive Assessment
    • Lengthier test of cognition (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
  • ADMARK testing looks at tau and amyloid levels, also of limited help

 

Management

  • Targeting Cognitive Impairment
    • Cholinesterase Inhibitors: Donepezil, rivastigmine
    • 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
    • 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)