DETERIORATION OF GENERIC KNOWLEDGE IN PATIENTS WITH ALZHEIMERS-DISEASE - EVIDENCE FROM THE NUMBER INFORMATION TEST

Semantic memory for generic knowledge was assessed in patients with pr obable Alzheimer's disease (AD; n = 142) and elderly normal control (N C; n = 78) subjects using the Number Information Test (NIT), a test th at consists of 24 general knowledge questions that require a single nu mber for an answer (e.g., ''How many days are in a year?''). The resul ts showed that patients with AD were impaired, even in the mildest sta ge of dementia, and that this impairment grew as the severity of their dementia increased over time. In addition, patients with AD were high ly consistent in the individual items they missed in subsequent test s essions conducted 1 or 2 years later. These results indicate that sema ntic memory for generic knowledge is impaired relatively early in AD, deteriorates throughout the course of the disease, and may be due to a loss of knowledge rather than to a retrieval deficit.