Central auditory processing. V. Ear advantages for acoustic stimuli in baboons

Four baboons (Papio cynocephalus) were tested using food as reward for ear advantages in the monaural discrimination of pure tones, three-tone musical chords, synthetically constructed consonant-vowels, and vowels. All four animals showed highly significant and reproducible ear advantages for each class of acoustic stimulus with marked individual differences in the direction of their ear asymmetry. The results obtained in these experiments represent the first evidence of ear asymmetries for different classes of acoustic stimuli in a nonhuman species. Further, the ear advantages found in these animals under monaural conditions resemble those obtained with dichotic presentation in human subjects and thus suggest that the baboon may be a valuable model of central auditory processing of various types of acoustic stimuli in man.     

Dichotic listening pattern in conduction aphasia

This paper reports a finding of hemispheric brain asymmetry for speech in short-gestation infants (mean gestational age = 36 weeks). Using a new measure—degree of reduction in limb tremors following exposure to speech stimuli compared to two control groups, one hearing orchestral music, the other no patterned stimuli—we found that speech disproportionately affected right limb movements. It is not clear whether the effect is due to asymmetries in cortical or subcortical processing. This provides evidence against the notion that brain specialization for language functions necessarily appears over time; rather, specialization for some functions (e.g., speech reception) must be present at birth.     

Cerebral organization of oral and signed language responses: case study evidence from amytal and cortical stimulation studies

A normally hearing left-handed patient familiar with American Sign Language (ASL) was assessed under sodium amytal conditions and with left cortical stimulation in both oral speech and signed English. Lateralization was mixed but complementary in each language mode: the right hemisphere perfusion severely disrupted motoric aspects of both types of language expression, the left hemisphere perfusion specifically disrupted features of grammatical and semantic usage in each mode of expression. Both semantic and syntactic aspects of oral and signed responses were altered during left posterior temporal-parietal stimulation. Findings are discussed in terms of the neurological organization of ASL and linguistic organization in cases of early left hemisphere damage.     

Dichotic listening ear asymmetry: Patterns of longitudinal development

Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.     

Trait attributions and defense against insult from a dissimilar other

It was hypothesized that subjects would prefer to blame a character assault on negative ability characteristics of a dissimilar attacker as opposed to negative motivational characteristics in order to escape responsibility for the attack. It was reasoned that because we generally think of ourselves as having less potential influence over the abilities as opposed to the motivations of another person, it might be possible to diminish one's responsibility for another's behavior by attributing that behavior to that person's ability characteristics. Subjects in this experiment responded either to an insulting or noninsulting stimulus person who was either similar or dissimilar by selecting from a list of both motivational and ability bipolar trait dimensions, those dimensions they would most prefer to use in rating the stimulus person. As predicted, subjects responding to an insulting and dissimilar stimulus person showed a significantly greater preference for ability trait dimensions than subjects in the other conditions combined and also disliked the stimulus person more. The significance of these results for defensive attribution processes and phenomena such as racism and sexism are discussed.     

Hemiplegic writing in severe aphasia

Three patients with severe aphasia and right hemiplegia are described who could write to dictation with the right arm using a limb prosthesis though agraphic with the "intact" left hand. The phenomenon of "hemiplegic writing" is explained as an access to submerged or preprocessing levels in language and action structure, through the use of older proximal motor systems. This interpretation has implications for our understanding of language and brain function, as well as for approaches to the treatment of patients with severe language disorders.     

Laterality differences in speaker and consonant identification in dichotic listening

Two dichotic listening experiments assess the lateralization of speaker identification in right-handed native English speakers. Stimuli were tokens of /ba/, /da/, /pa/, and /ta/ pronounced by two male and two female speakers. In Experiment 1, subjects identified either the two consonants in dichotic stimuli spoken by the same person, or identified two speakers in dichotic tokens of the same syllable. In Experiment 2 new subjects identified the two consonants or the two speakers in pairs in which both consonant and speaker distinguished the pair members. Both experiments yielded significant right-ear advantages for consonant identification and nonsignificant ear differences for speaker identification. Fewer errors were made for speaker judgments than for consonant judgments, and for speaker judgments for pairs in which the speakers were of the same sex than for pairs in which speaker sex differed. It is concluded that, as in vowel identification, neither hemisphere clearly dominates in dichotic speaker identification, perhaps because of minor information loss in the ipsilateral pathways.     

Production of narrative discourse in aphasia

The study described the abilities of a group of 15 moderately impaired aphasics and 15 normals to produce narrative discourse. The experimental tasks included telling stories, summarizing stories, and giving morals to stories. The data were analyzed in terms of sentential grammar, discourse grammar, and subjective ratings of content and clarity of language. The results showed that aphasics produced well-structured discourse. The language of the aphasics' discourse was reduced in both complexity and amount, as compared to that produced by normals. The reduction of language reflected selective reduction of hierarchically organized information. The findings of the study confirm the results of previous research on mildly impaired aphasics, which also showed preservation of discourse structure with selective reduction of information.     

Phonemic imperception in aphasia

This study investigated characteristics of 14 aphasics with impaired phoneme discrimination identified from a population of 100 patients with left hemisphere lesions. All patients with impaired phoneme discrimination were significantly impaired in aural comprehension, but many showed intact sound recognition and some showed normal reading comprehension. Defects in phoneme discrimination were typically seen in the acute stage of aphasia resulting from stroke; and in most instances, defects in phoneme discrimination were no longer apparent 4 months postonset. All patients who recovered normal phoneme discrimination also made significant improvement in aural comprehension. The findings support the concept that some aural comprehension defects result from a specific disturbance in phoneme discrimination.     

Gerstmann syndrome without aphasia: a longitudinal study

A case of "pure" and complete Gerstmann syndrome resulting from a focal vascular lesion in the posterior parietal area of the left hemisphere and not associated with aphasic disorder or general mental impairment is described. The initial symptom presentation of this patient supported the concept of the autonomous nature of the Gerstmann aggregate but longitudinal findings suggested that these symptoms did not in fact represent a coherent syndrome.     

A human sound transducer/reproducer: Temporal capabilities of a profoundly echolalic child

Stimulus-echo latencies of a blind, severely echolalic child were measured to assess the capabilities of spontaneous transduction/reproduction of a verbal signal. Mean offset-to-onset latencies of 270 msec and onset-to-onset latencies of 792 msec are comparable to laboratory reaction times for syllable imitation. Results are considered within the theoretical context of physiological speech, i.e., externalized exposure of a psittacine level of verbal processing divorced from semantic, syntactic, lexical and, quite probably, phonological interference.     

The development of procedures for identifying competitive behavior in children

This study identified events in the competitive process that could be employed to discriminate between competition and individual, non-social behaviors. When children competed they overtly sought out information on how they were doing vis-à-vis their fellow competitor. In addition, their performance was a function of some competitive contingency: a reward for surpassing another. The procedures developed in this study were designed to manipulate competitive contingencies while observing their effects on task performance and social comparisons. The investigator could thus infer that competition was present when (1) subjects sought out information on how they were doing, as well as how another was doing on comparable tasks during competitive contingencies, and (2) their task performance was a function of the competitive contingency.     

Acoustic cues for the perception of place of articulation in aphasia

Two experiments assessed the abilities of aphasic patients and nonaphasic controls to perceive place of articulation in stop consonants. Experiment I explored labeling and discrimination of [ba, da, ga] continua varying in formant transitions with or without an appropriate burst onset appended to the transitions. Results showed general difficulty in perceiving place of articulation for the aphasic patients. Regardless of diagnostic category or auditory language comprehension score, discrimination ability was independent of labeling ability, and discrimination functions were similar to normals even in the context of failure to reliably label the stimuli. Further there was less variability in performance for stimuli with bursts than without bursts. Experiment II measured the effects of lengthening the formant transitions on perception of place of articulation in stop consonants and on the perception of auditory analogs to the speech stimuli. Lengthening the transitions failed to improve performance for either the speech or nonspeech stimuli, and in some cases, reduced performance level. No correlation was observed between the patient's ability to perceive the speech and nonspeech stimuli.     

Phonetic disintegration in aphasia: Acoustic analysis of spectral characteristics for place of articulation

In this study, we attempted to determine whether phonetic disintegration of speech in Broca's aphasia affects the spectral characteristics of speech sounds as has been shown for the temporal characteristics of speech. To this end, we investigated the production of place of articulation in Broca's aphasics. Acoustic analysis of the spectral characteristics for stop consonants were conducted. Results indicated that the static aspects of speech production were preserved, as Broca's aphasics seemed to be able to reach the articulatory configuration for the appropriate place of articulation. However, the dynamic aspects of speech production seemed to be impaired, as their productions reflected problems with the source characteristics of speech sounds and with the integration of articulatory movements in the vocal tract. Listener perceptions of the aphasics' productions were compared with acoustic analyses for these same productions. The two measures were related; that is, the spectral characteristics of the utterances provided salient cues for place of articulation perception. An analysis of the occurrences of errors along the dimensions of voicing and place showed that aphasics rarely produce utterances containing both voice and place substitutions.     

Phoneme errors in Broca's aphasia: three Finnish cases

The phonemic errors of three Finnish Broca's aphasics were analyzed according to various phonological features, frequency of segments, syllable, word, and stress positions, as well as for the phonotactic structure of the uncanonical products. It was found, e.g., that the distance between the syntagmatic error and its source could not be satisfactorily counted by phonemes, since the syllable had to be taken into account also in pathological Finnish. As regards the paradigmatic dimension of the errors, the number of incorrect features is even here in reverse relation to the frequency of the erroneous phonemes. Moreover, it was found that pure quantity errors and vowel harmony deviations are infrequent in the speech of Finnish Broca's aphasics.     

Role and justice considerations in the attribution of responsibility to a rape victim

This study was designed to assess the extent to which social role and “just world” considerations would affect perceptions and attributions of responsibility to a rape victim. The rape victim was either a topless-bottomless dancer, a social worker, or a Catholic nun, and she was either acquainted or unacquainted with her assailant. In the acquainted condition, the dancer was attributed the greatest and the nun the least amount of responsibility, indicating that social role factors can govern the range of attributional judgments which might be made in any given instance. However, unacquainted victims were ascribed more responsibility for the rape than were acquainted victims, a difference which was significant when the victim was the nun. The latter findings are discussed in terms of Lerner's just world hypothesis. Significant sex differences were found in subjects' perceptions of and responses to the rape incident and, contrary to earlier findings, no relationship was found between victim attractiveness and punitiveness toward the wrongdoer.     

Comprehending homographs in aphasia

This study assessed 13 aphasic subjects' knowledge of the multiple meanings of homographs. The results indicated that the various meanings were less available to aphasic subjects than to normal subjects. In addition, specific meanings became less available as they became less typical although the number of meanings associated with a homograph did not influence performance. Aphasia type also did not influence performance. Performance on the experimental test was significantly correlated with auditory comprehension level and picture naming ability. The results were related to recent findings on semantic organization in aphasia.     

The occurrence of paraphasias in the spontaneous speech of children with an acquired aphasia

Two children with an acquired aphasia were observed during the recovery process. In the spontaneous speech, paraphasias belonging to different categories, such as neologisms, verbal paraphasias, and literal paraphasias, were found. Especially with regard to neologisms the time of investigation was very important. In addition, one child with a phonemic jargon aphasia and one child with a fluent aphasia and empty speech were observed. These observations implicate a modification of the current clinical picture of childhood aphasia. Some aspects are discussed in relation to adult aphasia.