Table 2

 Cortical versus subcortical dementia

FunctionCortical e.g. Alzheimer’s diseaseSubcortical e.g. Huntington’s disease
AlertnessNormal“Slowed up”
AttentionNormal earlyImpaired
Executive functionNormal earlyImpaired
Episodic memoryAmnesiaForgetfulness
LanguageAphasicReduced output
PraxisApraxiaRelatively normal
Perception ±visual/spacialImpairedImpaired
PersonalityPreserved (unless frontal type)Apathetic, inert