Studies in Neurolinguistics

Haiganoosh Whitaker,Harry A Whitaker

• Editore: Academic Press
• Anno: 2013
• ISBN:
  9781483265414
• Argomento: Sciences biologiques
• Categoria: Anatomie humaine et physiologie

Studies in Neurolinguistics, Volume 3 presents detailed case histories, multi-subject experimental studies, literature reviews, and research papers that employ a variety of experimental and observational techniques. This volume contains seven chapters that focus on a wide range of research in the field of neurolinguistics. Chapter 1 discusses the various approaches to the problem of auditory comprehension in aphasia. A survey of the world's literature on bilingualism and aphasia is provided in chapter 2. The third chapter examines the different models and explanations for conduction aphasia. Chapter 4 provides a synthesis of the anatomic, physiologic, and behavioral research on the role of the limbic system in human communication. Chapter 5 presents a model of individual differences in hemispheric functioning, in which a number of theories about the left and right hemispheres are analyzed and compared. Chapter 6 shows how different levels of language are revealed. The last chapter addresses "The Question of Electrophysiological Asymmetries Preceding Speech" in a study of the readiness potentials over the motor and premotor regions in eight subjects. Linguists, psychologists, and neurologists will find the book highly informative.

1

Auditory Comprehension in Aphasia¹

François Boller, Youngjai Kim and James L. Mack, CASE WESTERN UNIVERSITY, SCHOOL OF MEDICINE AND CLEVELAND VETERANS, ADMINISTRATION HOSPITAL

Publisher Summary

This chapter discusses the disturbances of auditory comprehension in aphasia. The comprehension of aphasics has been studied less than their expressions because the analysis of comprehension must be based on the observation of overt responses; it is thus confounded by output deficits. The chapter also discusses the early contributions to the study of comprehension deficits in aphasia and reviews various techniques that have been developed for the assessment of comprehension, including single tests and large test batteries. Aphasia is defined as the loss of language ability that is secondary to cerebral damage and that causes a disorder of translation of thoughts into words and words into thoughts. Within this broad definition, aphasic syndromes may be divided into two types: those with nonfluent and those with fluent output. About 20% of all patients with aphasia have Broca’s aphasia. The diagnosis of this form of aphasia is based on the observation of reduced verbal output in both speech and writing.

INTRODUCTION

This chapter deals with disturbances of auditory comprehension in aphasia. Although the most obvious aspect of an aphasic patient’s disturbance is his oral, written, or gestural output, it was recognized quite early in the history of aphasia research that expressive problems were often associated with impairments of comprehension. Nevertheless, the comprehension of aphasics has been studied less often than their expression, perhaps because the analysis of comprehension must be based, of course, on observation of overt responses and thus is confounded by output deficits. While a disorder of spontaneous output can be reasonably interpreted as an expressive disorder, a deficient response to an external stimulus may or may not reflect impairment of comprehension per se.

It is quite difficult to provide a precise definition for the term “comprehension.” Most would agree, however, that a disorder of comprehension is an inability to understand linguistic utterances which cannot be attributed to deficient sensory input, generalized cognitive deficits, or defective attention. This chapter consists of an analysis of disorders of auditory comprehension in adult aphasics. Impaired comprehension of written (see Marshall & Newcombe, this volume) or gestural material (see Gainotti & Lemmo, 1976) is not discussed.

A brief outline of the commonly used categories of aphasia is presented in order to indicate the extent to which comprehension deficits have been considered to be associated with each such category. Other, nonaphasic syndromes which result or appear to result in comprehension difficulties are also described. After discussing some early contributions to the study of comprehension deficits in aphasia, we review various techniques that have been developed for the assessment of comprehension, including single tests and large test batteries. Finally, an analysis of experimental studies of auditory comprehension is presented.

COMPREHENSION DISORDERS IN VARIOUS SYNDROMES

The terminology used in this section and in the remainder of this chapter is generally that proposed by Benson and Geschwind (1971) and Goodglass and Kaplan (1972). For each syndrome, however, the terms used by other authors are also indicated. Aphasia is defined as a loss of language ability that is secondary to cerebral damage and that causes a disorder of translation of thoughts into words and words into thoughts. Within this broad definition, aphasic syndromes may be divided initially into two types, those with nonfluent and those with fluent output (Benson, 1970).

Nonfluent Aphasias

BROCA’S APHASIA

This syndrome corresponds to what Broca (1861) called aphemia, later referred to by Wernicke (1874, 1908) and Goldstein (1948) as motor aphasia. Other synonyms include cortical motor aphasia (Lichtheim, 1885), verbal aphasia (Head, 1926), expressive aphasia (Weisenburg & McBride, 1935), and efferent motor aphasia (Luria, 1966). The diagnosis of this form of aphasia is based principally on the observation of reduced (nonfluent) verbal output in both speech and writing. Comprehension often appears intact or nearly intact on informal examination. In fact, it is rarely perfect, as shown by the poor performance of patients when asked to carry out complex commands requiring a succession of responses. Written questions and commands are particularly likely to elicit defective responses (Isserlin, 1936). In some cases, comprehension is more grossly impaired, so there may be considerable overlap between this form of aphasia and global aphasia. Not infrequently, an initial global aphasia evolves, as the patient’s comprehension and output improve, into a typical Broca’s aphasia. About 20% of all patients with aphasia have Broca’s aphasia (Vignolo, 1973).

GLOBAL APHASIA

Weisenburg and McBride (1935) called this syndrome expressive–receptive aphasia. The most deficient of all types, the global aphasic shows severe impairment of all linguistic functions. He says little, understands only a few questions and commands, and repeats only the simplest sounds. It is not unusual to observe this condition initially followed by a residual picture of another type of aphasia (as, for example, Broca’s aphasia, as just stated). Global aphasia is the most frequent type of aphasia (20 to 25%; Vignolo, 1973).

TRANSCORTICAL MOTOR APHASIA

Transcortical motor aphasia is Lichtheim’s (1885) term; Luria,(1966) described a somewhat similar condition he called dynamic aphasia. Patients with this syndrome have markedly reduced output with relatively intact comprehension. Naming is also quite good; repetition is practically perfect. Reading is preserved, but writing is nearly always impaired. In the case of those patients whose reduced output is linguistically correct and who can name, understand, repeat, and read quite well, it is doubtful that the disorder is an aphasia, a fact that led Von Stockert (1974) to dub the syndrome aphasia sine aphasia.

Fluent Aphasias

WERNICKE’S APHASIA

The disorder we know as Wernicke’s aphasia was referred to by Wernicke, 1874 and Goldstein (1948) as sensory aphasia, while Lichtheim,(1885) called it sensory cortical aphasia, and Head, syntactic aphasia(1926; cf., for example, his Case 14, Vol. 2, p. 215). Luria refers to it as acoustic aphasia(1966); Weisenburg and McBride,(1935) term it receptive aphasia. Diagnosis is based principally on the observation of fluent yet meaningless jargon. Alajouanine, Sabouraud, and Ribaucourt (1952) and Alajouanine, Lhermitte, Ledoux, Renaud, and Vignolo (1964) have described two, sometimes coexistent types of this disorder, distinguished by their tendencies to use primarily phonemic or semantic jargon, a distinction discussed in detail later (see pp. 34–36). In a retrospective analysis of his own cases, Hécaen (1969, 1972) has differentiated Wernicke’s aphasia into three forms: (a) “predominant word-deafness,” in which there is impairment in the reception of auditory signals but a relatively preserved ability to read; (b) “predominant impairment of verbal comprehension,” with inability to decode both oral and written language; and (c) “attentional disorganization,” with failure to attend consistently to messages.

In Wernicke’s aphasia, comprehension, as a rule, is severely impaired, but some patients with severe jargonaphasia can show good performance on tests of auditory comprehension (Alajouanine, Sabouraud, & de Ribaucourt 1952; Kinsbourne and Warrington, 1963). The typical patient, when questioned or given commands, usually stops talking and appears to listen to what he is told, only to fall back into a jargon that often bears no apparent relationship to the examiner’s words. The incidence of Wernicke’s aphasia is similar to that of Broca’s apahsia, that is, 15 to 20 % (Vignolo, 1973).

CONDUCTION APHASIA

Conduction aphasia was a term introduced by Wernicke (1874). Goldstein calls it central aphasia (1948), and Luria’s afferent motor aphasia (1966) probably corresponds to this form. Wernicke (1874) thought that, in some patients, there could be a lesion of the pathway connecting “the central termination of the acoustic nerve,” what we now call “Wernicke’s area,” and the areas controlling “the representation of movements in the cerebral cortex which are necessary for the production of sounds,” or “Broca’s area” in modern parlance. Thus Wernicke chose the term Leitungsaphasie, which implies “failure to conduct.” He noted that these patients could “understand everything” and “express themselves” but that their “ability to choose the correct word is disturbed.” As was pointed out later (Lichtheim, 1885), these patients repeat quite poorly. Diagnosis is often based on a discrepancy between relatively preserved comprehension and clearly impaired repetition. Varying data on the incidence of this type of aphasia have been reported, from “rare” (Goldstein, 1948) to 4% (Vignolo, 1973) and 5 to 10% (Benson, Sheramata, Bouchard, Segarra, Price, & Geschwind, 1973).

ANOMIC APHASIA

Synonyms for this type of aphasia include amnestic aphasia (Wernicke, 1874) and nominal aphasia (Head, 1926). Here the main disturbance consists of difficulties in naming on confrontation and in word-finding in spontaneous speech. The naming and word finding problems occur with a wide variety of word types and must be distinguished from problems in naming specific types of stimuli, such as colors or other visual or tactual stimuli. The latter type of difficulty is seen in nonaphasic agnosic conditions which Geschwind (1967a) considers to reflect lesions which separate specific sensory systems from the speech areas. Nonaphasic misnaming may occur with diffuse or generalized neurological involvement as well. Actual anomic aphasics represent about 8% of the total number of cases of aphasia (Vignolo, 1973).

TRANSCORTICAL SENSORY APHASIA

The name transcortical sensory aphasia was proposed by Lichtheim (1885). Von Monakow (1914) calls it sensory associative aphasia. In this syndrome repetition is quite good while comprehension is grossly impaired. In extreme cases, repetition is the only remaining language function, a condition leading to echolalia. This more severe form was called by Goldstein (1948) and by Geschwind, Quadfasel, and Segarra (1968) “isolation of the speech area.” The name transcortical sensory aphasia is thus reserved for the less severe form in which comprehension, though somewhat preserved, is clearly worse than repetition. This syndrome ...

Indice dei contenuti

• Cover image
• Title page
• Table of Contents
• PERSPECTIVES IN NEUROLINGUISTICS AND PSYCHOLINGUISTICS
• Copyright
• List of Contributors
• Preface
• Contents of Previous Volumes
• Chapter 1: Auditory Comprehension in Aphasia
• Chapter 2: Bilingualism and Aphasia
• Chapter 3: The Nature of Conduction Aphasia: A Study of Anatomic and Clinical Features and of Underlying Mechanisms
• Chapter 4: The Limbic System in Human Communication
• Chapter 5: A Model of Individual Differences in Hemispheric Functioning
• Chapter 6: Variability and Constraint in Acquired Dyslexia
• Chapter 7: The Question of Electrophysiological Asymmetries Preceding Speech
• Subject Index