Eleanor M. Saffran

Dissociations of language function in dementia: a case study.

Abstract In this report we describe and attempt to characterize the deterioration in semantic knowledge occurring in a victim of a progressive dementing disease. The subject was unable to match even highly familiar naming words with their actual or pictured referents; instead, she consistently overextended verbal labels to closely associated distractors. The alteration in scope of referential meanings suggested by this overextension effect was apparently related to a breakdown in the structure of underlying categories. On a nonverbal match-to-sample procedure, for example, dogs were treated as exemplars of the cat family. Evidence for the breakdown of semantic knowledge was not limited to picture labeling paradigms. Thus, we found that the subject was unable to utilize semantic context in the written disambiguation of spoken homophones but could, at the same time, use even minimal syntactic cues as the basis for proper lexical selection. This last result was consistent with other lines of evidence pointing to the relative preservation of syntactic operations, in marked contrast to the semantic loss. The importance of this dissociation of function in organic pathology is considered from a number of perspectives, including its relevance to models of language organization in the brain.

The word order problem in agrammatism ☆: I. Comprehension

Abstract The results of a picture-pointing comprehension test show that agrammatic aphasics have difficulty understanding sentences in which the underlying semantic roles are marked by the order of noun phrases around a verbal element. Agrammatic patients performed poorly on reversible constructions involving spatial prepositions (e.g., “The square is above the circle”) and verbs (e.g., “The dancer applauds the clown”). These results have significance for the interpretation of the underlying disturbance in agrammatism—whether the deficit is syntactic or purely phonological.

Immediate memory for word lists and sentences in a patient with deficient auditory short-term memory

This study of a patient with a mild conduction aphasia again traces impaired repetition to faulty auditory short-term memory. In serial recall, for example, the normal recency effect was absent with auditory but not visual lists. The patients behavior in immediate memory tasks was in some ways more characteristic of delayed recall, suggesting that an intact long-term memory was responsible for the residual short-term performance. The patient also showed a remarkable ability to paraphrase sentences he could not repeat verbatim, a result which has implications for the role of auditory memory in language comprehension.

The word order problem in agrammatism: II. Production

Abstract This study demonstrates that agrammatic aphasics have difficulty describing relations that are signified by the order of noun phrases around verbs or prepositions. The word order deficit is found in a Sentence Order Task, in which written words must be arranged linearly to form a sentence, as well as in oral production. Ordering tendencies reflect factors like animacy or potency, rather than the systematic use of syntactic rules. These results point to a fundamental syntactic disorder in agrammatism.

Reading without phonology: Evidence from aphasia

This study of an aphasic dyslexic supports the view that there are separate visual and phonological pathways in reading. The patient retained a reading vocabulary of at least 16 500 words although she was unable to perform operations that critically depend on grapheme-to-phoneme conversion; these included reading nonsense words, recognizing rhymes and homophones, and accessing lexical entries from homophonic spellings such as “kote”. Typographical variation, such as mixed case presentation, did not interfere with her reading performance, which suggests that it is mediated by letter identification rather than by a wholistic method of word recognition. The total performance pattern strongly suggests that this patient identifies words by matching particular letter-strings with their corresponding meanings.

DISSOCIATIONS OF LANGUAGE IN APHASIA: IMPLICATIONS FOR NORMAL FUNCTION*

The language disorders that result from organic brain disease have mostly been used to answer anatomical questions: which areas of the brain subserve language? The concern of this paper is to show that pathological data can also be used to study the normal language process; that they are relevant for a theory of language function, as well as for the eventual ascription of that function to the brain. We hope that this will emerge from the data that comprise the second part of the paper. The first part, a general consideration of the neuropsychological approach to the study of language function, is included here in an effort to correct some prevailing misconceptions.

An analysis of speech perception in word deafness

Abstract A patient with a rather pure word deafness showed extreme suppression of right ear signals under dichotic conditions, suggesting that speech signals were being processed in the right hemisphere. Systematic errors in the identification and discrimination of natural and synthetic stop consonants further indicated that speech sounds were not being processed in the normal manner. Auditory comprehension improved considerably however, when the range of speech stimuli was limited by contextual constraints. Possible implications for the mechanism of word deafness are discussed.

Semantic mechanisms in paralexia.

Abstract This study explores the effects of semantic constraints on the occurrence of paralexic responses in two patients who tend to produce semantic errors in reading aloud. In the first experiment, semantic constraints were provided by using words as proper names (e.g., “brown” vs. “Sam Brown”), and in the second by using short, highly familiar phrases to restrict the meaning of the target word (e.g., the polar bear; green with envy). These constraints were found to be effective in reducing the frequency of paralexic errors.

Reading in deep dyslexia is not ideographic.

Abstract Reading that is not phonologically mediated is often assumed to be “wholistic” or “ideographic” in nature. This study demonstrates that patients who are unable to read by use of spelling-sound correspondence rules (“deep” or “phonemic” dyslexics) have the capacity to read words presented in unusual configurations (vertical and mixed-case presentation). This evidence suggests that these patients are using a non-phonological reading mechanism that is based on letter information rather on overall configuration.

Origins and Distribution of Language

Implicit in the title of this chapter is the promise that we will try to relate the evolutionary history of language to the current distribution of language function in the brain. Unfortunately, this is a promise we are unable to fulfill. At present there are simply too few points of contact between these two areas of limited knowledge for one to inform the other.