Louis J. Gerstman

Enhancement of naming in nonfluent aphasia through gesture

In a number of studies that have examined the gestural disturbance in aphasia and the utility of gestural interventions in aphasia therapy, a variable degree of facilitation of verbalization during gestural activity has been reported. The present study examined the effect of different unilateral gestural movements on simultaneous oral-verbal expression, specifically naming to confrontation. It was hypothesized that activation of the phylogenetically older proximal motor system of the hemiplegic right arm in the execution of a communicative but nonrepresentational pointing gesture would have a facilitatory effect on naming ability. Twenty-four aphasic patients, representing five aphasic subtypes, including Brocas, Transcortical Motor, Anomic, Global, and Wernickes aphasics were assessed under three gesture/naming conditions. The findings indicated that gestures produced through activation of the proximal (shoulder) musculature of the right paralytic limb differentially facilitated naming performance in the nonfluent subgroup, but not in the Wernickes aphasics. These findings may be explained on the view that functional activation of the archaic proximal motor system of the hemiplegic limb, in the execution of a communicative gesture, permits access to preliminary stages in the formative process of the anterior action microgeny, which ultimately emerges in vocal articulation.

In search of closure: Subjective contour illusions, gestalt completion tests, and implications ☆

This study investigates the construct validity of perceptual closure tests (CTs), and isolates a common processing demand from the right-hemisphere. Sixty-seven patients with focal unilateral lesions (34 right side, 33 left side), and 80 control subjects participated. Multivariate analyses indicated that there was substantial age-related variance in all CTs, while sex was variably significant; CTs are not uniform in their discriminating ability, and hence factorially complex; and their specifically right hemisphere-sensitive dimension was subjective contour illusions, and interestingly unrelated to facial discrimination ability. The methodological and theoretical implications are discussed.

Impact of emotional content on discourse production in patients with unilateral brain damage.

A picture story task was developed to examine expression of emotion via the verbal/lexical channel. The task elicited discourse with either emotional, visual-spatial, or neutral content and was administered to right brain-damaged (RBD), left brain-damaged (LBD), and normal control (NC) right-handed adults. Subjects were matched for gender, age, education, and occupational status. The brain-damaged groups were matched for months post-CVA onset and were similar with respect to intrahemispheric site of lesion. While the number of words produced was equivalent for each of the subject groups, the RBDs and LBDs expressed quantitatively less content than did the NCs. When content differences were examined within each subject group, there were no differences for LBDs and NCs, but the RBDs showed a selective deficit when producing emotional content. This finding suggests a special role for the right hemisphere in the production of emotional content in verbal discourse.

The Perception of English Stops by Speakers of English, Spanish. Hungarian, and Thai: A Tape-Cutting Experiment

American English stops, including residual stops,i.e., stops in /s/-clusters after the removal of the /s/, were presented in front of stressed vowels for identification on the one hand to native speakers of American English, on the other, to native speakers of Puerto Rican Spanish, Hungarian, and Thai, languages with differences in the phonetic composition of their stop phonemes. Speakers of American English identified the residual stops with the voiced (lenis) stop; the others, with the voiceless stop. The results suggest that there is a hierarchic organization among the features of these stops: the lack of aspiration tends to force the evaluation of stops in the direction of /b, d, g/ in American English, whereas in the languages where other distinctions exist, the evaluation is different.

Evidence for differentiation of right hemisphere visual-perceptual functions

Performance on tasks sensitive to right hemisphere dysfunction (facial discrimination and perceptual closure) are reported in eight patients with right hemisphere lesions. Patients demonstrated an apparent double dissociation of performance on the two measures. Site-by-task specificity for the closure task was strongly suggested. Implications for right hemisphere organization and underlying psychological processes are considered.

An Artificial Talker Driven from a Phonetic Input

This paper describes a method of producing artificial speech from a phonetic input, i.e., symbols representing the names of phonemes corresponding to a given text are fed into a machine and the acoustic waveforms of connected speech emerge. The experimental work was accomplished on an electronic computer (IBM 7090), but the scheme is simple enough to permit realization with analog hardware. The talking machine program is divided into two parts. The first part simulates a more or less conventional resonance synthesizer of the tandem variety, requiring nine control signals; buzz intensity, hiss intensity, pitch, plus the center frequencies and bandwidths of three formants. Initially, this part of the program was used alone in experiments for which the inputs were detailed specifications of the control signals derived from spectrograms and physiological data, sampled at approximately three times the phonemic rate. Results from this phase were later combined with known results in speech perception to produce ...

A process model of repetition in aphasia: an investigation of phonological and morphological interactions in aphasic error performance.

Articulatory errors made by a group of aphasic subjects in the repetition of words and nonsense syllables were analyzed with reference to a five part process model of repetition. Results indicated that the number of cognitive units within stimuli were a major factor in the number, type, and position of error, and that a segmentation process, both grammatically and phonetically dependent, was operating in the responses. Overall, the results were interpreted to support a “reduction of efficiency” view of aphasia.

Random Generation of Apparent Speech Rhythms

In order to illustrate the misinterpretation of time series data, simulated temporal patterns of vocalizations and pauses were generated from a table of random digits. These data exhibited precisely those characteristics which, when seen in graphs of actual spontaneous speech, have heretofore been taken as evidence for cognitive planning. This concretizes a previously made point concerning the need to distinguish random process from causal connection.

Breathing Mixture and Depth as Separate Effects on Helium Speech

Two divers made tape recordings of standard vocabularies while breathing several different helium‐oxygen mixtures in a decompression chamber maintained at various simulated depths between sea level and 600 ft. Spectrographic analyses confirmed previous reports of nonlinear formant‐frequency shifts and changes in relative formant amplitudes, but failed to reveal improvements with time in talker intelligibility, especially at the lowest depths. A mathematical model, incorporating both the effects of helium concentration and of depth, was found to account successfully for the observed changes in formant frequencies. The model has also been employed in a real‐time speech correction device, the output of which represents a significant improvement in helium‐speech intelligibility. [Work supported by Ocean Systems, Inc.]

Syntactical versus Temporal Cues for Speaker Switching in Natural Dialogue

Intercomparison of two data domains permits an assessment of the relative importance of pauses and syntax as determinants of speaker switching in spontaneous dialogue. The pause and switching data derive from the output of the automatic vocal transaction analyzer, which samples the presence and absence of each participants speech every 300 msec. The syntactic data derive from boundary markings (points of linguistically permissible phrase endings) on 10 642 words of text transcribed from four 15‐min dialogues. Synchronization of both data bases revealed that switching occurs nine times more often after pauses than after nonpauses, and 21 times more often after boundaries than after nonboundaries. The two effects are nonadditive, since the co‐occurrence of both cues makes switching 42 times more likely than the co‐occurrence of neither. When in conflict, the synthetic cue outweighs the pause cue, since switching occurs 2.6 times more often after a nonpausal boundary than after a nonboundary word followed b...