Long-term phonatory instability in ataxic dysarthria.

AIMS: Long-term phonatory instability can be quantified using cyclical and noncyclical measures. The objective of this study is to evaluate phonation in ataxic dysarthria and a control group of normal speakers to answer two main questions: (1) How common is elevated cyclical and noncyclical instability in ataxic dysarthria compared to that in a normal control group? (2) Is cyclical instability predictive of noncyclical instability? METHODS: Vowel prolongations of ataxic-dysarthric and normal speakers were compared using the Motor Speech Profile module of the Computerized Speech Lab. Cyclical measures included tremor rate, amplitude and periodicity. Noncyclical measures included the coefficient of variation for loudness and frequency. RESULTS: Noncyclical measures are elevated in a subset of speakers with ataxic dysarthria regardless of whether cyclical instability (vocal tremor) is present. Cyclical instability was detected in nearly half the patients. Interestingly, elevations in both types of measures also described phonation of a number of the participants in the control group. CONCLUSION: Combined use of cyclical and noncyclical measures can document aspects of phonation in ataxic dysarthria that have clinical implications.

Charles Darwin and the evolution of human grammatical systems.

Charles Darwin's evolutionary theories of animal communication were deeply embedded in a centuries-old model of association psychology, whose prodromes have most often been traced to the writings of Aristotle. His notions of frequency of occurrence of pairings have been passed down through the centuries and were a major ontological feature in the formation of associative connectivity. He focused on the associations of cause and effect, contiguity of sequential occurrence, and similarity among items. Cause and effect were often reduced to another type of contiguity relation, so that Aristotle is most often evoked as the originator of the associative bondings through similarity and contiguity, contiguity being the most powerful and frequent means of association. Contiguity eventually became the overriding mechanism for serial ordering of mental events in both perception and action. The notions of concatenation throughout the association psychology took the form of "trains" of events, both sensory and motor, in such a way that serial ordering came to be viewed as an item-by-item string of locally contiguous events. Modern developments in the mathematics of serial ordering have advanced in sophistication since the early and middle twentieth century, and new computational methods have allowed us to reevaluate the serial concatenative theories of Darwin and the associationists. These new models of serial order permit a closer comparative scrutiny between human and nonhuman. The present study considers Darwin's insistence on a "degree" continuity between human and nonhuman animal serial ordering. We will consider a study of starling birdsongs and whether the serial ordering of those songs provides evidence that they have a syntax that at best differs only in degree and not in kind with the computations of human grammatical structures. We will argue that they, in fact, show no such thing.

Perseveration and other repetitive verbal behaviors: functional dissociations.

This article will review types of perseveration from a neurolinguistic perspective. During the course of the article, continuous, stuck-in-set, and recurrent perseveration will be placed in contradistinction to several other types of repetitive behaviors commonly associated with neurogenic communication disorders. These include echolalia in mixed transcortical aphasia; conduite d'approche and conduite d'ecart in fluent aphasias; lexical and nonlexical automatisms in nonfluent aphasias; palilalia in neuromotor disorders, such as Parkinson's disease (PD); and sound, syllable, word, and phrase repetitions in neurogenic stuttering. When differentiating these phenomena from perseveration, it is helpful to consider the salient factors that condition observed behaviors in individual patients, such as overall speech fluency, inventory of available utterances, nature of eliciting tasks, and propositionality of responses. Information such as communication disorder diagnosis, underlying etiology, and known sites of lesion from each patient's total clinical profile may also assist with differentiation.

Phonemic carryover perseveration: word blends.

This article will outline and describe the aphasic disorder of recurrent perseveration and will demonstrate how it interacts with the retrieval and production of spoken words in the language of fluent aphasic patients who have sustained damage to the left (dominant) posterior temporoparietal lobe. We will concentrate on the various kinds of sublexical segmental perseverations (the so-called phonemic carryovers of Santo Pietro and Rigrodsky) that most often play a role in the generation of word blendings. We will show how perseverative blends allow the clinician to better understand the dynamics of word and syllable production in fluent aphasia by scrutinizing the "onset/rime" and "onset/superrime" constituents of monosyllabic and polysyllabic words, respectively. We will demonstrate to the speech language pathologist the importance of the trochee stress pattern and the possibility that its metrical template may constitute a structural unit that can be perseverated.

Prosody in apraxia of speech.

Prosody is a complex process that involves modulation of pitch, loudness, duration, and linearity in the acoustic stream to serve linguistic and affective communication goals. It arises from the interaction of distributed neural networks that may be anatomically and functionally lateralized. Intrinsic prosody is mediated largely through left hemisphere mechanisms and encompasses those elements of linguistic microstructure (e.g., syllabic magnitudes and durations, basic consonantal and vocalic gesture specifications, and so) that yield the segmental aspects of speech. Extrinsic prosody is processed primarily by right hemisphere (RH) mechanisms and involves manipulation of intonation across longer perceptual groupings. Intrinsic prosody deficits can lead to several core symptoms of speech apraxia such as difficulty with utterance initiation and syllable transitionalization and may lead to the establishment of inappropriate syllable boundaries. The intrinsic prosody profiles associated with acquired apraxia of speech, developmental speech apraxia, and ataxic dysarthria may aid in the clinical differentiation of these disorders.