LINGUIST List 11.487

Tue Mar 7 2000

Review: Obler & Gjerlow: Language and the brain

Editor for this issue: Andrew Carnie <carnielinguistlist.org>


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  1. nschille, obler

Message 1: obler

Date: Mon, 6 Mar 2000 22:51:21 -0500 (EST)
From: nschille <nschillewjh.harvard.edu>
Subject: obler

Obler, Loraine K. and Gjerlow, Kris (1999), "Language and the 
Brain", Cambridge University Press, Cambridge (UK) (Cambridge 
approaches to linguistics). ISBN 0-521-46641-5. Paperback. xviii+206 
pp.

Reviewed by Niels Schiller, Harvard University


This book presents a brief introduction into "the study of language 
in the brain." The book is divided into twelve chapters, mostly 
focusing on language use in brain-damaged patients. Each chapter 
ends with a brief summary. The text part comprises 168 pages, 
followed by a glossary covering many of the technical terms from the 
field of neurolinguistics that are used in the volume. The glossary 
is followed by a very selective list of further readings, a list of 
references, an author index, and a subject index.

The book starts with an attempt to define more exactly what the 
study of neurolinguistics involves. Due to its multidisciplinary 
nature, this is a difficult job, but it seems to be clear that 
linguists, psycholinguists, neuropsychologists, as well as 
neurologists all have an interest in how language is structured in 
the brain. In the first chapter, the authors give a brief history 
about the field of neurolinguistics. They mention the classic works 
by Broca and Wernicke, as well as the Boston School and its role in 
modern aphasiology.

The second chapter provides a basic overview of the neuroanatomical 
structures in the brain. The reader is familiarized with the 
architecture of neurons and how neurons communicate with each other 
via electrochemical processes. Furthermore, the division of the 
cortex into lobes is described, and the most important gyri and 
sulci are briefly mentioned. The reader is also introduced to the 
well-known and still widely used division of the cortex by Brodmann 
(the so-called "Brodmann Areas").

Armed with this information, the authors present the most important 
research methodologies for localizing the hemispheric dominance for 
language in Chapter 3. These include the investigation of brain-
damaged patients, the anesthetizing of one hemisphere (the so-called 
"Wada test"), tachistoscopic presentation to only one visual field, 
dichotic listening, and the investigation of split-brain patients. 
Data from all of these methods suggest that the dominance of the 
left hemisphere for language for most people is uncontroversial. 
What is more difficult to determine is which areas in the left 
hemisphere are responsible for what kind of linguistic processing. 
Historically, research on this question began when Broca and 
Wernicke presented their patients more than 100 years ago. So-called 
"Broca's aphasics" are considered to be non-fluent in speech 
production while comprehension is relatively spared. In contrast, 
so-called "Wernicke's aphasics" are relatively fluent, but their 
speech usually contains a lot of circumlocutions and phonemic 
paraphasias, i.e., sound substitutions, rendering their speech hard 
to understand; their comprehension is severely impaired. With the 
help of cortical stimulation and, above all, modern brain imaging 
techniques such as PET, (f)MRI, and ERP, it is possible to localize 
lesions in brain-damaged patients and to identify the activity of 
brain areas in healthy subjects while they are engaged in certain 
linguistic tasks.

The next two chapters (Chapters 4 and 5) are about the 
classification of aphasic syndromes and their underlying symptoms. 
Aphasia is an impairment in the area of language without other 
cognitive deficits. Broca's and Wernicke's aphasia are described, 
but an introductory book like the present volume does not allow for 
explanations of much detail. What is helpful, however, is that the 
authors provide examples of what the speech of certain patients 
sounds like (usually descriptions of the "Cookie Theft" picture). 
Other forms of aphasia, such as conduction aphasia, anomic aphasias 
(naming problems), pure word deafness (due to injury to Heschl's 
gyrus), and subcortical aphasias are briefly mentioned as well. The 
phenomenon of agrammatism, i.e., speech production without producing 
the appropriate grammatical affixes and function words, is discussed 
relatively extensively. For example, the authors discuss questions 
such as the preserved syntactic competence in agrammatism and 
whether or not agrammatism should be considered a coherent syndrome. 
The authors further try to argue that Broca's aphasia, Wernicke's 
aphasia, and conduction aphasia can each be linked to a particular 
area in the brain. If this area is injured, the result is a 
characteristic deficit.

Chapter 6 is about childhood aphasia. It is basically about language 
acquisition and tries to make the connection to brain development in 
the child. The cases of Genie and other children with specific 
language impairment (SLI) are discussed. However, this chapter seems 
disconnected from the previous and the following chapter, and it is 
difficult for the reader to see the connection between this chapter 
and the rest of the volume. Maybe it would have been better to try 
and incorporate the facts about childhood aphasia in the previous 
chapters.

The next chapter (Chapter 7) talks about damage to the right 
hemisphere of the brain. Since aphasic syndromes are mostly -- but 
not always -- tied to the left hemisphere, the book up until this 
chapter focused primarily on the left hemisphere. However, certain 
aspects of linguistic processing, such as the processing of 
suprasegmental structures are mainly done by the right hemisphere. 
Therefore, it is important to also describe the consequences of 
right hemisphere damage for the use of language. Some studies on 
discourse production of right-hemisphere patients revealed some 
subtle deficits in verbal pragmatic aspects; other studies showed 
that these patients have difficulties with non-literal, that is, 
metaphoric usage of language. The chapter ends with a discussion of 
"split-brain" patients, i.e., patients in which the connection 
between the two hemispheres, the corpus callosum, has been cut in an 
attempt to treat severe epilepsy. Because the communication between 
the two hemispheres is interrupted in these patients, they provide a 
clear case for the investigation of the language abilities of the 
individual hemispheres. Michael Gazzaniga has done important 
research on these patients and found interesting results about the 
abilities of the individual hemispheres.

Chapter 8 focuses on dementia, e.g., as the result of Alzheimer's or 
Parkinson's disease, and its consequences for language processing. 
Patients with dementia experience word finding difficulties more 
frequently than healthy subjects. At this point, however, it is 
unclear whether word finding problems in Alzheimer's patients, for 
instance, are due to permanent loss of lexical representations or 
whether they are rather due to difficulty in accessing those 
representations. The problem of distinguishing between aphasic and 
demented patients is also discussed. Interestingly, the first author 
of this volume co-authored a paper claiming that one of the two 
supposedly aphasic patients presented by Wernicke in 1874 was 
clearly demented.

In the next chapter, Chapter 9, specific language deficits are 
discussed, namely dyslexia and dysgraphia. Both are impairments 
involve written language processing: dyslexia is a reading deficit, 
and dysgraphia is a spelling deficit. Developmental dyslexia 
(childhood dyslexia) and acquired dyslexia (caused by brain damage) 
have to be distinguished because they are caused by different 
syndromes. Developmental dyslexia is presumably caused by the 
inability to fully process the phonological input at a critical 
period, while acquired dyslexia is due to damage to the written word 
processing system. Several different forms of acquired dyslexia can 
be distinguished: surface dyslexia, i.e., the ability to read 
written input only via a non-lexical route (grapheme-to-phoneme 
conversion), and phonological dyslexia, i.e., reading written input 
only via the lexical route. Typically, surface dyslexics make errors 
on irregular words while phonological dyslexics cannot read pseudo-
words. If the semantic system in phonological dyslexics is also 
damaged, the deficit is referred to as "deep dyslexia". Typically, 
deep dyslexics make semantic errors in reading (e.g., producing 
"queen" in response to the written stimulus "king"). A disadvantage 
of an introductory volume like this is always that some issues 
cannot be discussed with enough depth. For example, the authors 
claim that processing differences between abstract and concrete 
words have been reported in dyslexic patients suggesting that these 
two types of words are organized differently in the lexicon. 
However, they do not say how abstract and concrete words might 
differ in their lexical representations. The discussion about 
dysgraphia is not satisfactory because it is much too short; 
slightly more than one page is clearly too little space for such a 
complex and well-studied deficit.

In Chapter 10, the authors discuss the phenomenon of bilingualism. 
Of special interest to the psycholinguist is of course the question 
of lexical organization in the bilingual (e.g., are the two lexicons 
of a bilingual completely separated or are they perhaps partially 
combined?). Presumably, a single semantic system maps onto language-
specific word forms in bilinguals. Unfortunately, the latest 
knowledge that we have about these questions did not make its way 
into this book (see latest issues of "Bilingualism: Language and 
Cognition", an international journal for the latest research in 
bilingualism). Recent experimental evidence by Costa, Miozzo, and 
Caramazza (1999) suggests that bilinguals, when producing speech, 
consider only words of the target language for lexical selection. In 
the chapter about bilingualism, phenomena such as code-switching and 
general second language acquisition abilities are also briefly 
mentioned.

In Chapter 11 the authors introduce linguistic theory. In this 
chapter, they try to tie these linguistic theories into what has 
been said earlier in the volume. On the one hand, this late 
discussion about linguistic theory has the advantage that all the 
data and facts about language and the brain have already been stated 
and can now be set into relation with the constructs of linguistic 
theory. On the other hand, this is a disadvantage for those readers 
who may have particularly little knowledge about linguistic theory; 
for less knowledgeable readers, it would have been better to discuss 
the basic linguistic levels in the beginning.

Finally, in the last chapter of this volume the authors make 
predictions about where the field of neurolinguistics will go in the 
future. The possible contributions and values of artificial 
intelligence, brain imaging, and neurophysiology are assessed, and 
the need for cross-linguistics studies is emphasized.

In summary, this is a decent introductory book about the study of 
language and the brain. Researchers in the field of aphasiology will 
probably not profit very much from it because the book is too basic. 
For the beginning student, however, it may be an ideal introduction 
because a broad range of topics is covered. The historic 
developments and classic papers are mentioned in the individual 
areas of research, and further readings are suggested. The 
individual chapters are relatively independent of each other and can 
be read independently. Unfortunately, very little is said about new 
imaging techniques and what their merits for the field may be. 
Nevertheless, the book seems to be an excellent source for a quick 
overview of the field of neurolinguistics. The truly interesting 
work, however, only starts once one gets involved into more specific 
issues. Due to space constraints, this volume cannot serve this 
purpose.

Bibliography

Costa, A., Miozzo, M., & Caramazza, A. (1999). Lexical selection in 
bilinguals: Do words in the bilingual's two lexicons compete for 
selection? Journal of Memory and Language, 41, 365-397.

Reviewer's biography

>From 1994 to 1998, the reviewer worked at the Max Planck Institute 
for Psycholinguistics in Nijmegen, The Netherlands. In 1997, he 
received his Ph.D. in Psychology from Nijmegen University. In his 
Ph.D. dissertation, he investigated the role of the syllable in 
lexical access during speech production. Since March 1998, he has 
been affiliated with the Cognitive Neuropsychology Laboratory of the 
Psychology Department at Harvard University in Cambridge, MA (USA). 
His research interests include phonological and morphological 
encoding in speech production, language processing in neurologically 
impaired patients, articulatory-motor processes during speech 
production, and forensic phonetics.
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