cortical versus frontal-subcortical dementia

Introduction

Cortical dementias have amnesia, aphasia, apraxia & disturbances of the cortical association areas. Alzheimer's disease exemplifies cortical dementia. Most other dementias have predominantly frontal-subcortical features from involvement of the frontal-subcortical circuits in the basal ganglia, thalamus & subcortical white matter (see below). Frontal-subcortical dementias are characterized by slowed mental processing, difficulty in memory retrieval, increased prominence of affective disturbances, relative sparing of language & presence of movement disorders. The AIDS dementia complex exemplifies frontal-subcortical dementia.

Features of cortical versus frontal-subcortical dementia:

• psychomotor speed
  • cortical: normal
  • frontal-subcortical: slow
• complex attention
  • cortical: normal
• frontal-subcortical: abnormal
• executive function
  • cortical: normal to abnormal
  • frontal-subcortical: abnormal
• information management
  • cortical: abnormal sequential steps
  • frontal-subcortical: abnormal for complex steps
• memory
  • cortical: amnesia (poor recognition)
  • frontal-subcortical: abnormal retrieval, cuing helps
• communication (language)
  • cortical: aphasia, anomia, decreased verbal fluency
  • frontal-subcortical:
    • dysarthria, decreased verbal fluency, perseveration with frontal involvement
• visuospatial
  • cortical: abnormal
  • frontal-subcortical: abnormal
• affect
  • cortical: unconcerned, unaware
  • frontal-subcortical: apathy, depression, disinhibition
• motor
  • cortical: normal
  • frontal-subcortical: abnormal movements, gait or tone

Additional terms

• aphasia
• attention assessment
• dysarthria
• executive function assessment
• memory assessment