Lambon Ralph M A, Graham K S, Ellis A W, Hodges J R
MRC Cognition and Brain Sciences Unit, Cambridge, UK.
Neuropsychologia. 1998 Aug;36(8):775-84. doi: 10.1016/s0028-3932(97)00169-3.
One of the major symptoms of semantic dementia (or progressive fluent aphasia) is profound word-finding difficulties. We present here a cross-sectional study of the factors affecting picture naming in semantic dementia based on data obtained from eight patients, together with a longitudinal analysis of naming in another patient. Various properties and attributes of the objects were entered into a series of regression analyses in order to predict which items the patients could or could not name. The analyses showed that object familiarity, word frequency and age-of-acquisition predicted naming success for the group and, in most cases, for each individual patient, irrespective of lesion site or overall naming success. We propose that the pattern of naming in semantic dementia is best described in terms of reduced semantic activation within a cascading/interactive speech production system. We suggest that object familiarity, and possibly word frequency, reflect the inherent robustness of individual semantic representations to the decay process in terms of both quantity and quality of experience. Age-of-acquisition and word frequency (at a phonological-lexical level) predicts naming success, because frequent, early-acquired words are relatively easy to activate even with reduced semantic "input".
语义性痴呆（或进行性流畅性失语症）的主要症状之一是严重的找词困难。我们在此基于从8名患者获得的数据，呈现一项关于影响语义性痴呆患者图片命名因素的横断面研究，并对另一名患者的命名情况进行纵向分析。将物体的各种属性和特征纳入一系列回归分析，以预测患者能够或无法命名哪些物品。分析表明，物体熟悉度、词频和习得年龄能够预测该组患者以及大多数情况下每个个体患者的命名成功率，而与病变部位或总体命名成功率无关。我们提出，语义性痴呆的命名模式最好用级联/交互式言语产生系统中语义激活减少来描述。我们认为，物体熟悉度以及可能的词频，在经验的数量和质量方面，反映了个体语义表征对衰退过程的固有稳健性。习得年龄和词频（在音系-词汇层面）能够预测命名成功率，因为频繁出现且早期习得的单词即使在语义“输入”减少的情况下也相对容易激活。
