Towards the identification of Idiopathic Parkinson's Disease from the speech. New articulatory kinetic biomarkers.

Although a large amount of acoustic indicators have already been proposed in the literature to evaluate the hypokinetic dysarthria of people with Parkinson's Disease, the goal of this work is to identify and interpret new reliable and complementary articulatory biomarkers that could be applied to predict/evaluate Parkinson's Disease from a diadochokinetic test, contributing to the possibility of a further multidimensional analysis of the speech of parkinsonian patients. The new biomarkers proposed are based on the kinetic behaviour of the envelope trace, which is directly linked with the articulatory dysfunctions introduced by the disease since the early stages. The interest of these new articulatory indicators stands on their easiness of identification and interpretation, and their potential to be translated into computer based automatic methods to screen the disease from the speech. Throughout this paper, the accuracy provided by these acoustic kinetic biomarkers is compared with the one obtained with a baseline system based on speaker identification techniques. Results show accuracies around 85% that are in line with those obtained with the complex state of the art speaker recognition techniques, but with an easier physical interpretation, which open the possibility to be transferred to a clinical setting.

A prosody tutorial for investigators of auditory sentence processing.

In this tutorial we present evidence that, because syntax does not fully predict the way that spoken utterances are organized, prosody is a significant issue for studies of auditory sentence processing. We describe the basic elements and principles of current prosodic theory, review the psycholinguistic evidence that supports an active role for prosodic structure in sentence representation, and provide a road map of references that contain more complete arguments about prosodic structure and prominence. Because current theories do not predict the precise prosodic shape that a particular utterance will take, it is important to determine the prosodic choices that a speaker has made for utterances that are used in an auditory sentence processing study. To this end, we provide information about practical tools such as systems for signal display and prosodic transcription, and several caveats which we have found useful to keep in mind.

The role of word structure in segmental serial ordering.

To test the hypothesis that similarity in position within the syllable provides an adequate description of the position constraints on segmental interaction errors in American English, five error elicitation experiments were carried out using sets of tongue-twisters based on pairs of confusable target consonants. Interaction errors increased when the two target segments shared position in the word onset, or before a stressed vowel, suggesting that these factors play an active role in the normal phonological encoding process.

Segmental durations in the vicinity of prosodic phrase boundaries.

Numerous studies have indicated that prosodic phrase boundaries may be marked by a variety of acoustic phenomena including segmental lengthening. It has not been established, however, whether this lengthening is restricted to the immediate vicinity of the boundary, or if it extends over some larger region. In this study, segmental lengthening in the vicinity of prosodic boundaries is examined and found to be restricted to the rhyme of the syllable preceding the boundary. By using a normalized measure of segmental lengthening, and by compensating for differences in speaking rate, it is also shown that at least four distinct types of boundaries can be distinguished on the basis of this lengthening.

The use of prosody in syntactic disambiguation.

Prosodic structure and syntactic structure are not identical; neither are they unrelated. Knowing when and how the two correspond could yield better quality speech synthesis, could aid in the disambiguation of competing syntactic hypotheses in speech understanding, and could lead to a more comprehensive view of human speech processing. In a set of experiments involving 35 pairs of phonetically similar sentences representing seven types of structural contrasts, the perceptual evidence shows that some, but not all, of the pairs can be disambiguated on the basis of prosodic differences. The phonological evidence relates the disambiguation primarily to boundary phenomena, although prominences sometimes play a role. Finally, phonetic analyses describing the attributes of these phonological markers indicate the importance of both absolute and relative measures.

Alterations in speech shadowing ability after cerebral injury in man.

Patients with penetrating wounds of the left cerebral hemisphere are inferior to normal control subjects and patients with right hemisphere lesions in their ability to shadow language stimuli presented at various rates. Their performance deteriorates rapidly at higher rates of stimulus presentation. Patients with bilateral cerebral penetration show similar patterns of deficits. The deficits on the shadowing task are especially prominent in patients who were dysphasic or dysarthric during the immediate postinjury period.

Color-contingent tilt aftereffect: spatial frequency specificity.

The stimulus specificities of the color-contingent tilt aftereffect resemble those involved in the McCollough aftereffect, with the major exception that the magnitude of the former increases monotonically with the spatial frequency of matched inducing and test gratings; this monotonic increase is not found for the achromatic tilt aftereffect. Like the McCollough aftereffect, the color-contingent tilt aftereffect is tuned to the spatial frequency of the inducing gratings and can be induced on both oblique and main axes of the retina.