Aspects of Multilingual Aphasia

Martin R. Gitterman, Mira Goral, Loraine K. Obler

• Publisher: Multilingual Matters
• Year: 2012
• ISBN:
  9781847697561
• Topic: Medicine
• Subtopic: Audiology & Speech Pathology

This volume provides a broad overview of current work in aphasia in individuals who speak more than one language. With contributions from many of the leading researchers in the field, the material included, both experimental work and theoretical overviews, should prove useful to both researchers and clinicians. The book should also appeal to a broader audience, including all who have an interest in the study of language disorders in an increasingly multicultural/multilingual world (e.g. students of speech-language pathology and linguistics). The areas of multilingual aphasia addressed in this collection include assessment and treatment, language phenomena (e.g. code-switching), particular language pairs (including a bidialectal study), and the role of cultural context.

Part 1

Broad Considerations

1	The Study of Bilingual Aphasia: The Questions Addressed
	Loraine K. Obler and Youngmi Park

Introduction

Educated 19th-century Europeans were well aware that Europe was home to many multilinguals as well as monolinguals. Of course the early debates about language organization in the brain that observation of aphasia patterns permitted intended to address the questions of universals of human language representation. Thus it followed that questions about language patterns in bilinguals and multilinguals would be among the issues that scholars addressed. In this chapter, we consider the questions that have been asked concerning bilingual and multilingual aphasia from that period to the present.

The first focus of interest concerned the question of which language returned first, and whether it was the first or most-used language (Freud, 1891; Pitres, 1895). Such reports provided the literature with interesting individual case studies and series of case studies well into the 20th century.

As understanding of lateral dominance for language grew in the mid-20th century, the question arose of whether multilingualism resulted in more crossed aphasia (aphasia in a right-hander resulting from a right-hemisphere lesion) than was seen in monolinguals with aphasia (e.g. Gloning & Gloning, 1965). By the late 1970s, more fine-grained questions were being asked about the patterns of impairments across the languages of multilingual individuals with aphasia, the patterns of recovery from their aphasia and the factors that determined these (Obler & Albert, 1977; Paradis, 1977).

With the expansion of treatments for aphasia in the later 20th century came a set of studies of the effectiveness of such treatments in the languages of the multilingual (Fredman, 1975; and Watamori & Sasanuma, 1978, among the first). These have led to a recent series of more experimental studies on the topic in the 21st century, some of which also ask whether enhanced brain activation can be seen post-therapy.

In what follows we review the chronology of questions asked in the research on multilingual aphasia, considering the implicit as well as explicit questions addressed in each era. We focus at somewhat greater length on the more recent studies that have been less frequently reviewed, concluding with those questions that may be on the cutting edge of our topic.

Studies of Recovery Patterns

In this section we cover the questions of the late 19th century and first three-quarters of the 20th century concerning which language returns first, what patterns of impairment and recovery are seen, and where in the brain a mechanism for switching between languages can be found. The general rule for impairment patterns in aphasia is that there is the same kind of aphasia in all the languages, and the degree of impairment is proportional to the degree of proficiency the patient had in each language prior to the aphasia-producing incident. However, today, as in prior centuries, there have been cases where this rule did not hold, and these are the ones that provoked the question of what determines recovery patterns.

While there must have been substantial numbers of multilinguals whose aphasia impairment and recovery were unremarkable, we now have a literature of over 200 cases where differential recovery was reported. The two explanations that dominated the first 80 years of studying this question were whether the first language would return first, as Ribot predicted in his book Disease of Memory (1881) and Freud asserted in his book On Aphasia (1891). The alternative that Pitres proposed was that the language that had been used most around the time of the accident was the one most likely to recover better (Pitres, 1895). At one point it appeared that Pitres’ rule held with greater than chance accuracy, at least in individuals with onset of aphasia before age 60 (Obler & Albert, 1977), but in a later analysis of additional cases the picture became murkier. So, it would seem that the answer to that question is that neither the rules of Pitres nor of Ribot hold with greater than chance accuracy (Obler & Mahecha, 1991). However, in the early–mid 20th century, a new alternative was added to the question, asking to what extent emotional attitudes to one’s languages played a role in predicting relative impairment. Authors such as Minkowski (1963) and Krapf (1955) reported single-case studies to make the point that an unusual pattern of recovery appeared to be linked to particular emotional attachments or dislikes.

Only with Paradis’ (1977) taxonomy did the questions concerning differential impairment and recovery take a step back from simplistic causal ones to consider the complexity of impairment patterns as they play out over the course of recovery. Much more detailed analyses of language patterns emerged as linguists and speech-language pathologists joined neurologists in the study of multilingual aphasia. The questions became ones about what specific pattern was seen among the six patterns that Paradis detailed in his 1977 article and others that he reported with colleagues in later articles (e.g. Paradis, 2001). In Fabbro (1999), we see that these have led to the further classification of interesting phenomena in the field (e.g. recovery of a never-previously spoken language such as Classical Greek, or of a language previously used only for religious purposes, such as Latin). Fabbro (1999) also briefly addresses questions such as what happens in bilingual aphasia in children.

Lateral Dominance in Multilinguals

Having addressed these two localizationist questions, the next we will cover is whether multilinguals have more right-hemisphere involvement in language than monolinguals. By the mid-20th century, lateral dominance was a major focus of study in the field of neurolinguistics. Two techniques, although imperfect, had evolved to study it non-invasively in healthy individuals: tachistoscopic visual recognition and dichotic-listening techniques. This may have been what prompted Gloning and Gloning (1965) to write about the small series of cases they saw in Austria of multilinguals who had aphasia resulting strictly from right-hemisphere lesions, a phenomenon that the previous literature – also virtually entirely from Europe, one must note – had reported was extremely rare. A few follow-up studies found the question interesting, and reported a small series of such crossed aphasia. However, when consecutive series of patients coming to a neurology clinic were systematically studied, the number of instances of crossed aphasia proved not to be disproportionately large in multilinguals (Charlton, 1964; April & Tse, 1977). Nevertheless, the question of additional right-hemisphere involvement in multilinguals, either for language generally, or for first or later-learned, more or less proficient second languages (L2s), remains unresolved. Indeed, the level of analysis employed in these early lateral dominance studies is quite coarse relative to the greater specificity of lesion-site or processing-site that imaging techniques afforded in the late 20th and early 21st centuries.

The Language Switch: Where Is It?

One knows that healthy multilinguals are able to speak in the language of those they are speaking with, switching languages or avoiding doing so when appropriate. The ability to do so must lie in the brain, so by the logic of neurolinguistics, one has only to look at a group of patients with problems limited to inappropriate switching in order to discover what region is involved in switching. The only problem with this logic arose when the cases that were reported showed no overlap whatsoever in lesion location. Parietal, temporal and frontal lobe sites have been linked to the phenomenon in the earlier literature (e.g. Fabbro et al., 1997).

A recent functional neuroimaging study has shown crucial brain areas for language switching by asking what regions underlie the behavior of people with aphasia who show what we term ‘inappropriate language switching’, that is, what Abutalebi et al. (2009: 143) term ‘interference from the non-target language’ that occurred during spontaneous speech and naming tasks.¹ Abutalebi et al. (2009) provided language therapy to a bilingual (L1: Spanish/L2: Italian) with aphasia due to a cerebral hemorrhage affecting the subcortical area (the left lenticular nucleus and surrounding areas) at three months post-onset. Before the beginning of the treatment, L1 (Spanish) was better than L2 (Italian) during spontaneous speech and naming tasks. The language treatment was provided in L2 (Italian). The first treatment phase lasted for six weeks and this treatment focused on naming which was deficit-specific. The second four-week treatment phase which focused on improving global language abilities then followed. Improvement of the treated language (L2, Italian) was observed and performance of L2 became better than that of L1 after the first treatment phase, and, finally, L2 naming skills became normal at the end of the second phase.

At the beginning of the treatment, between-language errors (inappropriate language switching) from L1 (the better language, Spanish) to L2 (Italian) were often observed when testing L2, but switching from L2 to L1 was not observed during L1 testing. However, with improving L2 naming skills, after the two treatment phases, such inappropriate switching became uncommon when naming pictures in L2 (Italian, the treated language). However, the participant unintentionally did this form of switching by naming in L2 when required to name in L1 (Spanish, the untreated language).

This behavioral result, wherein a shift in the inappropriate switching was linked to language improvement, was observed in their functional magnetic resonance imaging (fMRI) data as well. Before the treatment phases began, the pattern of brain activity was similar for L1 and L2. However, neural reorganization was found only in L2 after language treatments. When the participant performed better in L1 than L2, brain regions associated with language control, monitoring and detecting potential errors, such as the prefrontal cortex, the caudate and the anterior cingulate cortex (Abutalebi & Green, 2007, 2008; Crinion et al., 2006), were activated during L1 production. By contrast, activation of only the anterior cingulate cortex was observed during L2 production. However, after the first treatment phase, although the left caudate was still activated in L1, no other areas were activated. In contrast, activation of the prefrontal cortex, the caudate and the anterior cingulate cortex was now observed for L2. Then, no further activation of these language control areas was found for L1 after the end of the treatment phases. Abutalebi et al. (2009) postulate that this functional shift of control areas from L1 to L2 resulted in the different language-switching pattern evident in the shifting recovery pattern of the patient’s two languages.

While the phenomenon of switching still remains of great interest, it is fair to say that the aphasia literature has not resolved it, nor have those undertaking neuroimaging with non-brain-damaged individuals resolved it either (but see Abutalebi & Green, 2007, 2008; Hernandez et al., 2000; Hernandez et al., 2001). This is most likely due to the fact that not a region but a diffuse system – probably all or part of the system governing executive functions – is involved in giving the multilingual the ability to appropriately address interlocutors. It may, however, also be due to the differing definitions of what constitutes a problem with ‘switching’. Switching impairment may mean inability to switch to a non-L1 language, as is often seen in dementia, or it may mean borrowing a word from one language to use in another as a strategy – deliberate or not – to deal with anomia as, one might argue, in the Abutalebi et al., 2009 case discussed above. These two forms of switching are commonly seen. Another possibility, however, would be violation of code-switching norms between languages. In such a case, the patient might switch at a syntactic juncture different from where switching occurs in healthy participants, or within a word, or NOT switch in conversation where switching would be expected. To our knowledge such switching problems have not been reported in multilinguals with aphasia.

Bilingual Aphasia Therapy: What is the Directionality of Generalization?

A recent review (Lorenzen & Murray, 2008) has covered the clinical implications of the literature on bilingual aphasia; here we consider the theoretical clinical questions. Usually one language is chosen when aphasia therapy is provided to bilinguals due to the limited number of bilingual speech-language pathologists and/or a patient and family’s preference or needs. Therefore, many researchers have investigated the question of whether cross-language generalization can result from the treated language to a non-treated language (e.g. Edmonds & Kiran, 2006; Gil & Goral, 2004; Goral et al., 2010; Miertsch et al., 2009) and some researchers have tested which language (either L1 or a later language) or language elements (e.g. cognates or non-cognates) should be targeted to maximize treatment gains in a non-treated language (e.g. Croft et al., 2011; Edmonds & Kiran, 2006; Kohnert, 2004). Additionally, recent studies on bilingual aphasia treatment efficacy have reported brain activation changes using fMRI along with language performance changes before and after aphasia therapy (e.g. Abutalebi et al., 2009; Marangolo & Rizzi, 2009; Meinzer et al., 2007).

Although bilingual aphasia therapy has resulted in improvement of language skills in bilinguals in general (Faroqi-Shah et al, 2010), inconsistent cross-language generalization patterns have been found so far. As Kohnert and Peterson (Chapter 6, this volume) report, some researchers have observed cross-language generalization after aphasia therapy (e.g. Gil & Goral, 2004; Miertsch et al, 2009), others have reported that cross-language generalization is limited to certain items or a certain language (i.e. to a more proficient language or to a less proficient one) (e.g. Edmonds & Kiran, 2006; Kohnert, 2004) and the remaining researchers (e.g. Abutalebi et al, 2009; Galvez & Hinckley, 2003; Meinzer et al, 2007) have reported no generalization from the trained language to an untrained language.

The majority of studies have reported cross-language generalization as a result of aphasia therapy in one language. For example, in the study of Marangolo and Rizzi (2009), a Flemish- (L1) and Italian- (L2) speaking bilingual with aphasia with expressive language deficits received aphasia intervention in Italian at two months post-onset and the therapy lasted for six months. This participant showed a parallel recovery pattern during therapy and cross-language generalization was shown when his naming skills before and after treatment were compared. That is, although the treatment was provided in Italian, the same amount of improvement was found in both languages and there were no significantly different performance skills between the two languages at any time.

Among studies reporting cross-language generalization, there are a few that have asked whether aphasia therapy sessions in different languages are helpful as well. For example, Gil and Goral (2004) provided a series of aphasia therapy sessions to a Russian- (L1) and Hebrew- (L2) speaking late bilingual with aphasia who exhibited expressive and receptive language deficits in both languages starting at two weeks post-onset of his aphasia. Cross-language generalization was found after a month of language therapy in Hebrew. The patient presented parallel recovery of both languages in the receptive language deficits. However, after a three-and-a-half month continuation of the aphasia therapy in Hebrew, his non-treated Russian showed greater improvement than the treated Hebrew. At this time he demonstrated naming difficulty in Russian and receptive language deficits in Hebrew. Subsequently, aphasia therapy was provided in Russian for six weeks. Again, cross-language generalization was observed and the participant presented only naming difficulty in both languages at the end of therapy.

Similarly, Goral et al (2011) describe how they offered JM, a patient with severe non-fluent aphasia, intensive therapy in two of his five languages consecutively, testing his naming in each language pre-therapy and after each therapy block to determine how relative prof...

Table of contents

• Cover
• Titlepage
• Copyright
• Dedication
• Contents
• Contributors
• Introduction
• Part 1: Broad Considerations
• Part 2: Assessment and Treatment
• Part 3: Bilingual Language Phenomena
• Part 4: Language Pairs
• Part 5: Cultural Context
• Index