Episodic Memory in Patients with Semantic Dementia

Episodic Memory in Patients with Semantic Dementia

1. Semantic Dementia:

   • Progressive, selective loss of semantic memory - impaired on semantic memory, but fine with other memory systems,
   • Not a problem with language
   • Impaired when tested in any modality - e.g. words, pictures, sounds

2. Episodic Memory in Semantic Dementia

   • Patients very well orientated in time and place (episodic memory)
     • remember aspects of events (e.g. where they sat at a table, who was beside them)
     • can retrieve details of past events, particularly those experienced most recently,
     • good prospective memory (e.g. remembering to be ready at 5pm)
   • When asked about events from the past, speech is empty due to lack of semantic memory - the spatial and temporal info is there!
   • Almost opposite of amnesia - good episodic memory with poor semantic memory
     • They are distinct systems
   • Common tests used:
     • Present ps with an image and ask them to copy it - they are not significantly impaired (episodic memory). Patients do not know what the items are, but remember having seen them.
       • Double Dissociation between AD and SD patients - Alzheimer's p's have knowledge about items but cannot remember having seen them.

3. Anatomy of Different Memory Systems

   • Semantic Dementia:
   • Alzheimer's Disease