Aphasia Literature Research Articles

Evaluating Single-Subject Treatment Research: Lessons Learned from the Aphasia Literature

The mandate for evidence-based practice has prompted careful consideration of the weight of the scientific evidence regarding the therapeutic value of various clinical treatments. In the field of aphasia, a large number of single-subject research studies have been conducted, providing clinical outcome data that are potentially useful for clinicians and researchers; however, it has been difficult to discern the relative potency of these treatments in a standardized manner. In this paper we describe an approach to quantify treatment outcomes for single-subject research studies using effect sizes. These values provide a means to compare treatment outcomes within and between individuals, as well as to compare the relative strength of various treatments. Effect sizes also can be aggregated in order to conduct meta-analyses of specific treatment approaches. Consideration is given to optimizing research designs and providing adequate data so that the value of treatment research is maximized.

Direct attention training as a treatment for reading impairment in mild aphasia

Background: Although a variety of interventions for acquired reading disorders have been described in the aphasia literature, most have been designed for severe impairments. Individuals with mildly impaired reading characterised by inconsistent comprehension problems and/or by slower and variable reading rates, do not seem to benefit as much from these treatment approaches. These difficulties suggest relatively intact constituent reading processes that may be functioning inefficiently. Attentional deficits have been described in individuals with a variety of reading disabilities including acquired dyslexia. Although the treatment of nonlinguistic cognitive abilities such as attention has been suggested as an approach to improving language function in aphasia, little evidence exists documenting the treatment effectiveness of such interventions for aphasia in general, or reading in particular.Aims: The present study is a case report of an individual with mild aphasia whose primary complaint was reading difficulty. A treatment approach directed towards improving various aspects of attention was implemented. Aspects of reading were monitored as outcome measures. It was hypothesised that treatment based on attention training would facilitate improvements in this individual's reading.Methods & Procedures: The treatment programme was based on Attention Process Training–II (APT-II) (Sohlberg, Johnson, Paule, Raskin, & Mateer, 2001). The eight-week programme began with activities/tasks addressing sustained attention, and progressed through alternating, selective, and divided attention. Baseline and treatment probes consisted of the individual reading magazine articles and answering comprehension questions. Reading rate was also monitored.Outcomes & Results: The individual treated in this study progressed steadily through the APT-II programme. Treatment effects for improved reading comprehension and decreased reading rate were noted. In addition, changes in pre- and post-treatment test scores, reported reading effort, and reading enjoyment were also documented.Conclusions: The observed reading improvements were not felt to be the result of linguistic recovery. As this individual's proficiency to sustain attention, cope with distractions, and concentrate increased, her ability to read longer, more complex materials also improved. These results are consistent with previous studies that have noted improvements in nonlinguistic cognitive abilities of individuals with aphasia following direct intervention.

An errorless learning approach to treating dysnomia

Few errorless learning approaches to dysnomia treatment are found in the aphasia literature; none are found when paired with effortful rather than effortless learning (Fillingham, Hodgson, Sage, & Lambon Ralph, 2003). Grounded in Hebbian plasticity (Hebb, 1961), errorless learning occurs with increases in synaptic strength. Therefore, if a stimulus elicits an errorless response, Hebbian learning will strengthen the tendency to activate the same pattern of response on subsequent occasions. Our interest was in developing and piloting a treatment method of errorless and effortful learning cast in an ecologically valid framework of interactive discourse.

Aphasic Sentence Comprehension as a Resource Deficit: A Computational Approach

This article describes a new computational model of aphasic sentence comprehension. The model is based on the premise that all aphasics, however different, share a common deficit which determines a considerable amount of the individual variation observed in their sentence comprehension performance. This common deficit is construed as a pathological reduction in the activation resources of a working memory system that subserves sentence comprehension (Miyake, Carpenter, & Just, 1994). To test the theoretical feasibility of the resource reduction hypothesis, a new computer model of aphasic sentence comprehension was developed and tested. We describe the model as well as some initial simulation results, indicating that the model can account for some of the sentence complexity and severity effects that have been reported in the aphasia literature.

From first words to grammar in children with focal brain injury

The effects of focal brain injury were investigated in the first stages of language development, during the passage from first words to grammar. Parent report, free‐speech data, or both are reported for 53 infants and preschool children between 10 and 44 months of age. All children had suffered a single, unilateral brain injury to the left or right hemisphere, incurred before 6 months of age (usually in the pre‐ or perinatal period). This is the period in which one would expect to see maximal plasticity, but it is also the period in which the initial specializations of particular cortical regions ought to be most evident. In direct contradiction of hypotheses based on the adult aphasia literature, results from 10 to 17 months suggest that children with right‐hemisphere injuries are at greater risk for delays in word comprehension and in the gestures that normally precede and accompany language onset. Although there were no differences between left‐ and right‐hemisphere injury per se on expressive language, children whose lesions included the left‐temporal lobe showed significantly greater delays in expressive vocabulary and grammar throughout the period from 10 to 44 month s. No specific deficits were associated with left‐frontal damage, but there was a significant effect of frontal lobe injury to either hemisphere in the period from 16 to 31 months, when normal children usually show a burst in vocabulary and grammar. This bilateral effect of frontal damage is independent of motor impairment. Hence, there are specific effects of lesion site in early language development, but they are consistent neither with the lesion‐syndrome correlations observed in adults with homologous injuries nor with the literature on acquired lesions in older children. Results are used to argue against innate localization of linguistic representations, and in favor of an alternative view in which innate regional biases in style of information processing lead to familiar patterns of brain organization for language under normal conditions and permit alternative patterns to emerge in children with focal brain injury.

Johannes Schenck and Johannes Jakob Wepfer: Clinical and anatomical observations in the prehistory of neurolinguistics and neuropsychology

Historical observations of disorders of language have been reported from Pharaonic medical texts circa 3000 bc, the Hippocratic corpus circa 400 bc, Latin texts circa 1st century ad, through the Renaissance and in various 17th and 18th century texts. In none of the extant historical papers, however, have certain critical elements of aphasia been discussed, i.e. the distinction between a disorder of language and a deficit in its articulatory realization, nor the relation between aphasia and a left hemisphere lesion. This paper discusses the relatively unknown aphasia studies of two 16th and 17th-century physicians, J. Schenck and J. J. Wepfer, with respect to these critical elements. Johannes Schenck (1530–1598) assembled a collection of clinical observations from antiquity to those of his contemporaries; Vol. 1 ( Observationes Medicae de Capite Humano, Basel, 1584) discusses the pathology of the head and face, at least 16 cases of which refer to patients with aphasia. Johannes Jakob Wepfer (1620–1695) wrote a book on the vascularization of the brain and on apoplexy; in addition he wrote (published posthumously) a collection of neurological cases ( Observationes Medico-practicae de Affectibus Capitis Internis & Externis, Schaffhausen, 1727). In the latter he reported on 222 neurological and neurosurgical cases, at least 15 of which had an overt aphasia, almost all due to a left hemisphere lesion. The level of functional and anatomical detail in these case studies invites comparison with the best of the late 19th century classical aphasia literature.

Processing of negative morphemes in aphasia: An example of the complexities of the closed class/open class concept

The distinction between open class and closed class items is frequently made in contemporary aphasia literature, but it is not always clear that the users of these terms have a full awareness of the linguistic complexity of the concept. This paper thus begins with an extended discussion of some of these complexities, using adverbs, prepositions, and derivational affixes as examples. The paper then describes an experiment which investigated one area of English where the open/closed distinction is unclear, the area of negation. On a sentence-anagram picture-matching task, 25 aphasic subjects (principally non-fluent) responded significantly more accurately when the word cards that they were given to work with contained a negative prefix, such as un-, than when the word set contained the word not. It is suggested that this somewhat unexpected result may be attributable to the close link between derivational prefixes and the open-class words to which they attach.