Chris Code

Common brain regions underlying different arithmetic operations as revealed by conjunct fMRI-BOLD activation.

The issue of how and where arithmetic operations are represented in the brain has been addressed in numerous studies. Lesion studies suggest that a network of different brain areas are involved in mental calculation. Neuroimaging studies have reported inferior parietal and lateral frontal activations during mental arithmetic using tasks of different complexities and using different operators (addition, subtraction, etc.). Indeed, it has been difficult to compare brain activation across studies because of the variety of different operators and different presentation modalities used. The present experiment examined fMRI-BOLD activity in participants during calculation tasks entailing different arithmetic operations -- addition, subtraction, multiplication and division -- of different complexities. Functional imaging data revealed a common activation pattern comprising right precuneus, left and right middle and superior frontal regions during all arithmetic operations. All other regional activations were operation specific and distributed in prominently frontal, parietal and central regions when contrasting complex and simple calculation tasks. The present results largely confirm former studies suggesting that activation patterns due to mental arithmetic appear to reflect a basic anatomical substrate of working memory, numerical knowledge and processing based on finger counting, and derived from a network originally related to finger movement. We emphasize that in mental arithmetic research different arithmetic operations should always be examined and discussed independently of each other in order to avoid invalid generalizations on arithmetics and involved brain areas.

Analysing discourse in the traumatic brain injury population: telephone interactions with different communication partners

A range of discourse analyses are effective in identifying features which are aberrant following traumatic brain injury (TBI). We examined the exchanges of five traumatically brain-injured subjects and five matched controls across four speaking situations which included speaking to a therapist, to the bus timetable information service, to the police, and to their mothers on the telephone. Transcripts were analysed using the exchange structure analysis of systemic functional grammar. This analysis provided an indication of information giving (K1 moves per minute); information requesting and receiving (K2 moves per minute) and the amount of negotiation that was needed for the messages to be conveyed (dynamic moves per minute). Results indicated that the TBI subjects performed differently across the four conditions, and were differentiated from the matched controls on a number of measures. The role of different communication partners is also addressed. Communication partners were noted to interact differently with TBI subjects when compared with controls. This included increased information-giving to control subjects; more requests for information by police from TBI subjects and a greater use of dynamic moves by therapists with controls. The potential of exchange structure analysis is discussed as a useful way of examining the discourse of TBI subjects and their communication partners. Exchange structure analysis highlighted the dynamic nature of information exchange and the subtle ways speakers responded to familiarity and power imbalance in social interaction. This study has implications for family and community education regarding communication with people with TBI.

A multinational comparison of aphasia management practices

The effect of restructuring of healthcare on the quality, quantity, and nature of aphasia management is largely unknown. The current study is the first to examine access, diagnostic, treatment, and discharge patterns of patients with aphasia in Australia, Canada, the UK, the US private sector (US-Private), and the US Veterans Health Administration in the Department of Veterans Affairs (US-VA). The authors developed a 37-item survey to be completed by clinicians working with aphasic patients. The survey focused on eight areas: access to care, evaluation procedures, group treatment, number and duration of treatment sessions, limitations of the number of sessions, termination of treatment, follow-up practices, and resumption of treatment. 394 surveys were distributed and 175 were returned completed (44% return rate). Respondents represented a range of ages, work experiences, and work settings. There was considerable consistency among respondents from our five healthcare systems. Results suggest that patients may be routinely denied treatment in direct contradiction to the research literature. Just as we carefully monitor the progress of patients receiving our treatment, we are obliged to monitor the effects of managed care on our patients, fellow clinicians, and our profession.

The quantity of life for people with chronic aphasia

This study sought to examine the relationships between social activity and aphasia. Thirty-eight people with chronic aphasia and their closest relative completed a newly developed Social Network with Aphasia Profile (SNAP) and relatives completed a Communicative Effectiveness Index (CETI) during the summer months of the year 2000. The SNAP requires a record to be kept over a consecutive seven-day period of who the person with aphasia sees (e.g., doctor, brother), where they see them (e.g., hospital, gym, pub), and why (e.g., to attend group meeting, shopping). A multiple regression analysis was carried out using the number of hours people spent out of their home as the independent variable, and severity of aphasia, age, time since onset and presence of hemiplegia as dependent variables. This accounted for 30% of the variance and revealed that severity of aphasia has a particularly negative impact. Age and physical condition also have a negative impact. However, a rich social network was observed for some aphasic people. Only one participant was receiving speech-language therapy of two hours per week. Implications for reducing communication barriers, raising public awareness and service provision are discussed.

Models, theories and heuristics in apraxia of speech

This paper presents an examination of efforts to explain acquired apraxia of speech. The history of the disorder is sketched, its relation to other forms of apraxia and aphasia is discussed, and the evolutionary relationship between speech and action is addressed. Most research has been focused on whether apraxia of speech is best accounted for in terms of impairments at either an abstract-phonological level or a concrete-phonetic processing level, and the sum of the research concludes that it straddles traditional linguistic divides; it is an impairment in the transforming of phonological representation into phonetic fact. The issue is essentially a variant of the mind-body problem. Recent developments in phonological theory point to the importance of a less abstract phonology which is phonetically derived, phonetically constrained and phonetically dependent. Apraxia of speech provides a basis for an improved understanding of the nature of the control of speech processing.

The relevance of emotional and psychosocial factors in aphasia to rehabilitation

In this paper we review the relationship between the impact of aphasia and emotional well-being. Depression is one of several types of emotional response that has been researched most and we examine the different causes of depression for people with aphasia. We discuss the relationships between recovery and emotional state and the clinical and psychosocial implications of these relationships. We examine methods for assessment of emotional response and psychosocial evaluation and review implications for rehabilitation. We discuss briefly issues of drug treatment for depression in aphasic people. We conclude that the emotional impact of aphasia can have a marked negative impact on recovery, response to rehabilitation, and psychosocial adjustment.

Delivering for aphasia

Providing a quality service for people with aphasia is a primary goal of speech-language pathologists working with neurogenic communication disorders. This paper reviews what is known about the incidence and prevalence of aphasia and what services are provided for people with aphasia. On the basis of the stroke data, the incidence of aphasia in the developed world ranges between 0.02–0.06% with prevalence ranging between 0.1–0.4%. Average hours of treatment for aphasic people in the developed world ranges between 1–5 hours per week, with a great deal of variability, although recent research suggests that intense treatment of ∼9 hours per week over a relatively short period is needed in order to be effective. It is concluded that there is a significant gap between what the research suggests is the appropriate amount of treatment and actual provision throughout the English-speaking world.

Neurolinguistic Analysis of Recurrent Utterance in Aphasia

A linguistic analysis of 97 recurrent utterances (RUs) is reported which delineates 2 separate types of RU - Real Word Recurrent Utterances (RWRUs) and Non-Meaningful Recurrent Utterances (NMRUs). The range, frequency and distribution of phonemes occurring in RUs is similar to normal English in RWRUs, but not in NMRUs. NMRUs do not break the phonotactic constraints of the language and RWRUs rarely break the syntactic rules. It appears to be possible to classify RWRUs into certain groups among which a Pronoun + Verb and an Expletive group are the most interesting. Expletive RUs were all produced by male subjects and Pronoun + Verb RUs deserve further investigation. Implications for rehabilitation are discussed.

Multifactorial processes in recovery from aphasia: developing the foundations for a multileveled framework.

This paper develops the foundations for a framework of recovery from aphasia which attempts to integrate knowledge from several domains to form a basis for an approach to treatment as managed recovery. We still have a mainly operational appreciation of recovery derived from atheoretical group investigations using psychometric batteries and generic definitions of aphasia and a lack of clarity in the use of the terms restoration, compensation, and reorganization. There is a failure to appreciate the interrelation of different levels (e.g., neural, cognitive, behavioral) and the importance of different perceptions (e.g., patient, relative, clinician) in individual recovery. The multileveled framework may improve understanding of what underlies individual recovery and form a framework for mapping interactions between levels as a basis for intervention.

Can the Right Hemisphere Speak

While a capacity for the right hemisphere in language and language related functions is established, a role for the right hemisphere in speech production is controversial. The question of the nature of a possible right hemisphere speech production capability has centered mainly on the Jacksonian notion of nonpropositional speech. In this paper I examine whether the right hemisphere does have-a particular role in nonpropositional speech through an exploration of the neurophysiological evidence, research in aphasic speech automatisms, and degree of propositionality in the retained speech of adult left hemispherectomy patients.