Darley, Frederic L.

Phoneme duration control in utterances of various lengths was investigated in one apractic subject. Results indicate a loss of segment duration control and a speeding of intrasyllabic articulatory rates in apraxia. Findings are related to a theory of apractic speech dysfunction.

Twenty-seven schizophrenic patients free of any known neurologic deficit were tested with an aphasia test battery. The objective of the research was to derive a profile of schizophrenic language performance to permit its comparison with the profiles characteristic of aphasia, apraxia of speech, generalized intellectual impairment, and confused language. Results indicate that schizophrenic patients exhibit a profile of language performance distinctive from those found in aphasia, apraxia of speech, confusion, or generalized intellectual impairment and demonstrate that the disruption of language in schizophrenia is not aphasic in nature.

This study investigated the practicality of developing short forms of the Porch Index of Communicative Ability (PICA). Stepwise regression procedures were performed using data from 222 complete administrations of the PICA to determine the accuracy of prediction of overall scores on the basis of data from either fewer subtests or fewer items. Results indicated that the PICA is highly redundant and that it may be possible to develop useful shorter forms of it.

Two short versions (SPICAs) of the Porch Index of Communicative Ability (PICA)were developed and investigated, with specific attention to their ability to predict standard PICA overall scores of patients with aphasia. Ninety-three patients were administered three versions of the test in randomized order. Results indicate that SPICAs predict overall scores by standard administration at acceptable confidence levels in approximately one-third of the time required for the administration of the standard PICA.

Subjects were exposed to two sets of paragraphs that probed their auditory comprehension abilities under various prestimulation conditions. In Experiment 1, aphasic and control subjects listened to four paragraphs. Each paragraph was preceded by a control condition (no antecedent) or one of the following contextual antecedents: picture, verbal, or picture and verbal combined. Prestimulation with a picture alone was detrimental, but prestimulation with a picture used in combination with a verbal context appeared to be of value. In Experiment 2, subjects heard four paragraphs that were less cohesive than those in Experiment 1. Only verbal and control conditions were contrasted. The provision of prior verbal contexts facilitated the auditory comprehension of the paragraphs.

Thirty-second speech samples were studied of at least 30 patients in each of 7 discrete neurologic groups, each patient unequivocally diagnosed as being a representative of his diagnostic group. Three judges independently rated each of these samples on each of 38 dimensions of speech and voice using a 7-point scale of severity. Computer analysis based on the means of the three ratings on each patient on each dimension yielded results leading to these conclusions: (1) Speech indeed follows neuroanatomy and neurophysiology. There are multiple types or patterns of dysarthria, each mirroring a different kind of abnormality of motor functioning. (2) These patterns of dysarthria can be differentiated; they sound different. They consist of definitive groupings of certain dimensions of speech and voice, deviant to distinctive degrees. (3) Five types of dysarthria were delineated: flaccid dysarthria (in bulbar palsy), spastic dysarthria (in pseudobulbar palsy), ataxic dysarthria (in cerebellar disorders), hypokinetic dysarthria (in parkinsonism), and hyperkinetic dysarthria (in dystonia and chorea). Also, a mixed dysarthria combining elements of flaccid and spastic dysarthrias was identified in amyotrophic lateral sclerosis. (4) Observed occurrence of a single dimension uniquely in a given neurologic disease and distinctive co-occurrence of several dimensions can aid diagnostically in identification of neurologic disorders.

Three judges rated a number of speech characteristics of 20 patients with Wilson’s disease, an inherited metabolic disease. The perceptual data suggest the presence of a mixed dysarthria with prominent ataxic, spastic, and hypokinetic features which were predictable from neurologic data on the patients. Perceptual data on 10 patients, recorded at two specific points in a treatment program, indicate that speech can be used as an effective monitor of progress in the treatment of this disease.

Correlation matrices were used to demonstrate co-occurrence of deviant speech dimensions observed. Application of this technique led to the emergence of eight distinctive clusters of dysfunction. Each of seven neurologic disorders studied had its own unique group or pattern of clusters. However, any one cluster emerged in and was shared by more than one disorder. Inspection of the dimensions present in a cluster permitted giving the cluster a logically determined name based usually on the defective physiology responsible for the cluster. Knowledge of the neuromuscular characteristics of each disorder led to deductions concerning the neuromuscular substrate for each cluster. Intercluster correlations yielded clues concerning co-occurrence of certain neuromuscular defects. Further inspection led to identification of the probable neuromuscular bases of individual deviant speech dimensions. These conclusions may serve as hypotheses for more accurate physiologic and neurophysiologic measurements to further delineate the problems of dysarthria.

Twelve subjects with apraxia of speech and minimal aphasic involvement were tested in four experimental conditions: effects of instructions, the effect of three different experimentally imposed response-delay intervals on a word-repetition task, the effect of noise, and the effect of visual monitoring. Also studied in one or more of these conditions were the loci of errors in oral reading, the apraxic subjects' ability to predict and to recognize their errors, and the nature of the errors made. Under the conditions in which they were studied, instructions, response-delay intervals, noise, and visual monitoring had no significant influence on phonemic accuracy. Subjects with apraxia of speech had significantly more difficulty with three- syllable words than with one-syllable words. They made more errors on words weighted high (Brown’s word-weighting method) than on words weighted low; word length and grammatical class appeared to be important characteristics influencing increases in errors. The ability of apraxic subjects to predict errors appears to be an individual characteristic; the ability to recognize errors appears to be a group characteristic. Subjects consistently made substitution, repetition, addition, and omission errors. The results support the contention that apraxia of speech is a motor programming disorder.