Comparison of the recovery pattern in verb use in fluent and non-fluent aphasics in the first six months after stroke.

Abstract

Background: Verbs in aphasia is a widely studied topic in the past decades. A distinction can be made between fluent and non-fluent aphasic patients. In the traditional view fluent aphasics primarily show lexical-semantic deficits, while non-fluent aphasics have mainly syntactic deficits. Yet, several studies disputed this traditional view. Syntactic deficits were found in fluent aphasics as well and non-fluent aphasics indeed show lexical-semantic deficits. The underlying deficit was denounced and a deficit on integration level was introduced (Bastiaanse and Bol, 2001). A reverse relation between the verb diversity and inflection in non-fluent aphasics was found, in which individuals show a high verb diversity, but poor verb inflection or vice versa. Most studies examined the use of verbs in the chronic phase of aphasia and used data collected at one time point post stroke. Aims: The current study was designed to investigate (a) whether the reverse relation described by Bastiaanse and colleagues (and Jonkers, 1998; and Bol, 2001) is also found in fluent aphasics, (b) whether this reverse relation is also found in the acute phase of aphasia, (c) whether this reverse relation changes during recovery, (d) whether the relation in recovery has a reverse character as well and (e) whether two different tasks yield different results on all variables examined. Methods and Procedures: Two groups of aphasics, fluent and non-fluent, were included. Speech samples on a story retelling task and the spontaneous speech were analyzed at 2 weeks and 6 months post stroke. Type token ratio of verbs (verb diversity) and finiteness index (inflection ability) were calculated and compared both within and between groups. Results: In the group comparisons no reverse relation was found for either one of the groups at one time point post stroke. By examining the individual results, this reverse relation was found in both groups of aphasics. In the recovery, both groups of aphasics showed a reverse relation as well. In the comparison of two examined tasks, the spontaneous speech task showed a significant discrepancy between both groups of aphasics in the TTR and the story retelling task did not; in the FI no difference between the both tasks was found. Conclusions: A wide individual variability was found in both groups of aphasic patients. This appears to be the reason for the discrepancy between the group comparisons and the examination of the individual results. The majority of both fluent and non-fluent aphasic patients showed a presence of a reverse relation between verb diversity and inflection ability at 6 months post stroke. A reverse relation in recovery was found as well; one of the variables increased at the expense of the other variable, which decreased. The spontaneous speech task appeared to be more informative in examining reverse relations.