This thesis investigates impairments of written sentence comprehension in 14
aphasic adults. The primary purpose of the research was to apply computer
technology to the process of assessment, with the aim of improving diagnostic
precision and thereby being able to offer better-targeted and more effective
treatment.
To facilitate the study of sentence processing disorders a microworld was
developed, populated solely by animate and inanimate balls, boxes and stars.
This medium had two major advantages over natural English. Firstly, the
restricted vocabulary and the small set of grammatical structures used permitted
finer control of the linguistic environment, and secondly, all the test sentences
were fully reversible with equal plausibility. The microworld formed the basis for
a suite of patient-controlled computer programs dedicated to the study of two
functions: the processing of verbs and the processing of locative prepositions.
Computerisation enabled automatic, detailed and objective data collection in
assessment mode, freeing the observing clinician to make important
complementary observations. In remediation mode the software externalised the
subtasks of sentence comprehension for clinical study.
The results of an efficacy study are reported in which the aphasic subjects were
divided into two groups of seven and subjected to a cross-over design experiment.
Group A received verb treatment before preposition treatment and Group B
received the treatments in opposite order. Significant treatment effects were
obtained which could be attributed confidently to the intervention applied and
which included generalisation to 'real world' reading tasks. Many of the subjects
maintained benefit of treatment after a non-treatment interval of five months.
The thesis presents a range of new data on aphasic performances including details
of error patterns, response latencies and susceptibility of the different sentence
structures to treatment. In addition the aphasics are compared with 45 normal
subjects in their computer interface operation and on a new six-module Syntax
Screening Test. Theoretical contributions to knowledge are made in the
establishment of the dissociability of verb and preposition processing and in the
interpretation of the clinical observations. The microworld and software created
have potential application in many other areas of language research.