Cortical activation patterns of affective speech processing depend on concurrent demands on the subvocal rehearsal system. A DC-potential study

In order to delineate brain regions specifically involved in the processing of affective components of spoken language (affective or emotive prosody), we conducted two event-related potential experiments. Cortical activation patterns were assessed by recordings of direct current components of the EEG signal from the scalp. Right-handed subjects discriminated pairs of declarative sentences with either happy, sad or neutral intonation. Each stimulus pair was derived from two identical original utterances that, due to digital signal manipulations, slightly differed in fundamental frequency (F0) range or in duration of stressed syllables. In the first experiment, subjects were asked: (i) to denote the original emotional category of each sentence pair and (ii) to decide which of the two items displayed stronger emotional expressiveness. Participants in the second experiment were asked to repeat the utterances using inner speech during stimulus presentation in addition to the discrimination task. In the absence of inner speech, a predominant activation of right frontal regions was observed, irrespective of emotional category. In the second experiment, a bilateral activation with left frontal preponderance emerged from discrimination during additional performance of inner speech. Compared with the first experiment, a new pattern of acoustic signal processing arose. A relative decrease of brain activity during processing of F0 stimulus variants was observed together with increased activation during discrimination of duration-manipulated sentence pairs. Analysis of behavioural data revealed no significant differences in evaluation of expressiveness between the two experiments. We conclude that the topographical shift of cortical activity originates from left hemisphere (LH) mechanisms of speech processing that centre around the subvocal rehearsal system as an articulatory control component of the phonological loop. A strong coupling of acoustic input and (planned) verbal output channel in the LH is initiated by subvocal articulatory activity like inner speech. These neural networks may provide interpretations of verbal acoustic signals in terms of motor programs and facilitate continuous control of speech output by comparing the signal produced with that intended. Most likely, information on motor aspects of suprasegmental signal characteristics contributes to the evaluation of affective components of spoken language. In consequence, the right hemisphere (RH) holds a merely relative dominance, both for processing of F0 and for evaluation of emotional significance of sensory input. Psychophysically, an important determinant on expression of lateralization patterns seems to be given by the degree of communicative demands such as solely perceptive (RH) or perceptive and verbal-expressive (RH and LH).

Articulatory/phonetic sequencing at the level of the anterior perisylvian cortex: a functional magnetic resonance imaging (fMRI) study

Damage to the anterior peri-intrasylvian cortex of the dominant hemisphere may give rise to a fairly consistent syndrome of articulatory deficits in the absence of relevant paresis of orofacial or laryngeal muscles (apraxia of speech, aphemia, or phonetic disintegration). The available clinical data are ambiguous with respect to the relevant lesion site, indicating either dysfunction of the premotor aspect of the lower precentral gyrus or the anterior insula in the depth of the Sylvian fissure. In order to further specify the functional anatomic substratum of this syndrome, functional magnetic resonance imaging (fMRI) was performed during reiteration of syllables differing in their demands on articulatory/phonetic sequencing (CV versus CCCV versus CVCVCV). Horizontal tongue movements and a polysyllabic lexical item served as control conditions. Repetition of the CV and CCCV monosyllables elicited a rather bilateral symmetric hemodynamic response at the level of the anterior and posterior bank of the central sulcus (primary sensorimotor cortex), whereas a more limited area of neural activity arose within this domain during production of lexical and nonlexical polysyllables, significantly or exclusively lateralized toward the left hemisphere. There is neurophysiological evidence that primary sensorimotor cortex mediates the "fractionation" of movements. Assuming that the polysyllables considered are organized as coarticulated higher-order units, the observed restricted and lateralized cortical activation pattern, most presumably, reflects a mode of "nonindividualized" motor control posing fewer demands on "movement fractionation." These findings may explain the clinical observation of disproportionately worse repetition of trisyllabic items as compared to monosyllables in apraxia of speech. The various test materials failed to elicit significant activation of the anterior insula. If at all, only horizontal tongue movements yielded a hemodynamic reaction extending beyond the sensorimotor cortex to premotor areas. Since limbic projections target the inferior dorsolateral frontal lobe, the enlarged region of activation during horizontal tongue movements might reflect increased attentional requirements of this task.

Right-hemisphere dominance for the processing of sound-source lateralization

Cortical processing of change in direction of a perceived sound source was investigated in 12 human subjects using whole-head magnetoencephalography. The German word "da" was presented either with or without 0.7 msec interaural time delays to create the impression of right- or left-lateralized or midline sources, respectively. Midline stimuli served as standards, and lateralized stimuli served as deviants in a mismatch paradigm. Two symmetrically linked dipoles fitted to the mismatch fields showed stronger moments in the hemisphere contralateral to the side of the deviant. The right dipole displayed equal latencies to both left and right deviants, whereas left dipole latencies were longer for ipsilateral than contralateral deviants. Frequency analysis between 20-70 Hz and statistical probability mapping revealed increased induced gamma-band activity at 53+/-2.5 Hz to both types of deviants. Right deviants elicited spectral amplitude enhancements in this frequency range, peaking at latencies of 160 and 240 msec. These effects were localized bilaterally over the angular gyri and posterior temporal regions. Coherence analysis suggested the existence of two separate interhemispheric networks. For left-lateralized deviants, both spectral amplitude enhancements at 110 and 220 msec and coherence increases were restricted to the right hemisphere. In conclusion, both mismatch dipole latencies at the supratemporal plane and gamma-band activity in posterior parietotemporal areas suggested a right hemisphere engagement in the processing of bidirectional sound-source shifts. In contrast, left-hemisphere regions responded predominantly to contralateral events. These findings may help to elucidate phenomena such as unilateral auditory neglect.

Encoding of temporal speech features (formant transients) during binaural and dichotic stimulus application: a whole-head magnetencephalography study

Spoken-word recognition depends upon the encoding of relevant 'information bearing elements' of the acoustic speech signal. For example, relatively rapid shifts of spectral energy distribution (formant transients) cue the perception of stop consonant-vowel (CV) syllables such as /ba/, /ga/, and /da/. A variety of data indicate left-hemisphere superiority with respect to the processing of formant transients. To further delineate the underlying neurophysiological mechanisms, evoked cortical fields in response to CV syllables (oddball design; frequent stimulus=binaural /ga/; four deviant constellations: Binaural /ba/, binaural /da/, left /da/ (left ear deviant)-right /ga/, right /da/ (right ear deviant)-left /ga/) were recorded by means of whole-head magnetencephalography (MEG; 151 channels) under two different conditions of attentional demands (visual distraction versus reaction to prespecified stimuli). (a) During binaural stimulus presentation attention toward target events resulted in a significantly enhanced mismatch field (MMNm, magnetic analogue to the mismatch negativity) over the left as compared to the right hemisphere. In contrast, preattentive processing of the CV syllables failed MMNm lateralization effects. (b) Dichotic application of /da/ elicited a larger contralateral MMNm amplitude in subjects with right ear advantage (REA) at behavioral testing. In addition, right ear deviants yielded a stronger ipsilateral response than the left ear cognates. Taken together, these data indicate bilateral preattentive processing and subsequent attention-related predominant left-hemisphere encoding of formant transients at the level of the supratemporal plane. Furthermore, REA during dichotic application of CV syllables seems to be linked to functional dissociation of the two hemispheres during auditory processing.

Stroboscopic articulography using fast magnetic resonance imaging

A method to display dynamic aspects of vocal tract configuration during speech production by means of fast magnetic resonance imaging is presented. Data acquisition during repetitive movement relies on a stroboscopy-like procedure. The time resolution achieved is 120 images s-1 in a selected plane. As compared with other techniques of kinematic measurements of speech motor processes, this procedure allows for visualization of the temporal and spatial coordination of all relevant articulators, e.g. the entire tongue, the velum and the lower vocal tract. As an example, the method was applied to repetitions of stop consonant-vowel-nasal syllables.

Speech disorders following severe traumatic brain injury: kinematic analysis of syllable repetitions using electromagnetic articulography

Using electromagnetic articulography, the lips, the tip of the tongue, and the tongue dorsum were tracked during repetitions of the syllables [pa], [ta] and [ka] in 10 speakers with dysarthria following severe traumatic brain injury and in 10 age-matched control subjects. When asked to produce the syllable trains as fast as possible, the patient group showed a rather homogeneous pattern of movement abnormalities including prolonged syllable durations and reduced peak velocity/amplitude ratios. Most presumably, limited speed generation gives rise to the impaired ability to increase speech rate. During the habitual speaking condition, reduced velocity/amplitude ratios were restricted to the tongue tip and tongue dorsum. Obviously, the tongue and the lips are differentially affected in dysarthria following severe traumatic brain injury.

Opposite hemispheric lateralization effects during speaking and singing at motor cortex, insula and cerebellum

Aside from spoken language, singing represents a second mode of acoustic (auditory-vocal) communication in humans. As a new aspect of brain lateralization, functional magnetic resonance imaging (fMRI) revealed two complementary cerebral networks subserving singing and speaking. Reproduction of a non-lyrical tune elicited activation predominantly in the right motor cortex, the right anterior insula, and the left cerebellum whereas the opposite response pattern emerged during a speech task. In contrast to the hemodynamic responses within motor cortex and cerebellum, activation of the intrasylvian cortex turned out to be bound to overt task performance. These findings corroborate the assumption that the left insula supports the coordination of speech articulation. Similarly, the right insula might mediate temporo-spatial control of vocal tract musculature during overt singing. Both speech and melody production require the integration of sound structure or tonal patterns, respectively, with a speaker's emotions and attitudes. Considering the widespread interconnections with premotor cortex and limbic structures, the insula is especially suited for this task.

Lip-jaw and tongue-jaw coordination during rate-controlled syllable repetitions

The present study investigated the relationship between functionally relevant compound gestures and single-articulator component movements of the jaw and the constrictors lower lip and tongue tip during rate-controlled syllable repetitions. In nine healthy speakers, the effects of speaking rate (3 vs 5 Hz), place of articulation, and vowel type during stop consonant-vowel repetitions (/pa/, /pi/, /ta/, /ti/) on the amplitude and peak velocity of differential jaw and constrictor opening-closing movements were measured by means of electromagnetic articulography. Rather than homogeneously scaled compound gestures, the results suggest distinct control mechanisms for the jaw and the constrictors. In particular, jaw amplitude was closely linked to vowel height during bilabial articulation, whereas the lower lip component amplitude turned out to be predominantly rate sensitive. However, the observed variability across subjects and conditions does not support the assumption that single-articulator gestures directly correspond to basic phonological units. The nonhomogeneous effects of speech rate on articulatory subsystem parameters indicate that single structures are differentially rate sensitive. On average, an increase in speech rate resulted in a more or less proportional increase of the steepness of peak velocity/amplitude scaling for jaw movements, whereas the constrictors were less rate sensitive in this respect. Negative covariation across repetitions between jaw and constrictor amplitudes has been considered an indicator of motor equivalence. Although significant in some cases, such a relationship was not consistently observed across subjects. Considering systematic sources of variability such as vowel height, speech rate, and subjects, jaw-constrictor amplitude correlations showed a nonhomogeneous pattern strongly depending on place of articulation.

Characterisation of patients with primary biliary cirrhosis responding to long term ursodeoxycholic acid treatment

BACKGROUND

In some patients with primary biliary cirrhosis, ursodeoxycholic acid causes full biochemical normalisation of laboratory data; in others, indexes improve but do not become normal.

AIMS

To characterise complete and incomplete responders.

METHODS

Seventy patients with primary biliary cirrhosis were treated with ursodeoxycholic acid 10-15 mg/kg/day and followed up for 6-13 years.

RESULTS

In 23 patients (33%) with mainly stage I or II disease, cholestasis indexes and aminotransferases normalised within 1-5 years, except for antimitochondrial antibodies. Histological findings improved. Indexes were not normalised in 47 patients (67%) although the improvement of their biochemical functions parallelled the trend in the first group. In these incomplete responders histological findings improved to a lesser extent. The only difference between the two groups before treatment was higher levels of alkaline phosphatase and gamma glutamyl transpeptidase in the incomplete responders. At onset of treatment the discriminant value separating responders from incomplete responders was 660 U/l for alkaline phosphatase and 131 U/l for gamma glutamyl transpeptidase. One year later it was 239 and 27 U/l (overall predictive value for responders 92%, for incomplete responders 81%). There were no differences between the two groups concerning immune status, antimitochondrial antibody subtypes, liver histology, or any other data. HLA-B39, DRB1*08, DQB1*04 dominated in both groups.

CONCLUSIONS

In patients with mainly early stages of primary biliary cirrhosis, higher values of alkaline phosphatase and gamma glutamyl transpeptidase are the only biochemical indexes which allow discrimination between patients who will completely or incompletely respond to ursodeoxycholic acid treatment.

Preattentive processing of consonant vowel syllables at the level of the supratemporal plane: a whole-head magnetencephalography study

A variety of clinical and experimental data indicate superiority of the left hemisphere with respect to the encoding of dynamic aspects of the acoustic speech signal such as formant transients, i.e., fast changes of spectral energy distribution across a few tens of milliseconds, which cue the perception of stop consonant vowel syllables. Using an oddball design, the present study recorded auditory evoked magnetic fields by means of a whole-head device in response to vowels as well as syllable-like structures. Both the N1m component (=the magnetic equivalent to the N1 response of the electroencephalogram (EEG)) and various difference waves between the magnetic fields to standard and respective rare events (MMNm=magnetic mismatch negativity) were calculated. (a) Vowel mismatch (/a/ against /e/) resulted in an enlarged N1m amplitude reflecting, most presumably, peripheral adaptation processes. (b) As concerns lateralized responses to syllable-like structures, only the shortest transient duration (=10 ms) elicited a significantly enhanced MMNm at the left side. Conceivably, the observed hemispheric difference contributes to prelexical parsing of the auditory signal rather than the encoding of linguistic categories.

Oral budesonide and ursodeoxycholic acid for treatment of primary biliary cirrhosis: results of a prospective double-blind trial

BACKGROUND & AIMS

Ursodeoxycholic acid (UDCA) is used for treatment of primary biliary cirrhosis. Previous studies showed that, compared with UDCA monotherapy, bile salts plus prednisolone had no further effect on laboratory data but improved liver histology. Thirty percent of these patients had prednisolone-related side effects. Budesonide is a glucocorticoid with a high receptor affinity and a high first-pass metabolism. In this study we investigated whether budesonide and UDCA are superior to UDCA monotherapy.

METHODS

A 2-year prospective, controlled double-blind trial was performed. Twenty patients (mainly with early-stage disease) were treated with UDCA at a dose of 10-15 mg/kg daily in addition to 3 mg budesonide 3 times daily (group A), and 19 patients (1 dropped out for personal reasons) were treated with UDCA plus placebo (group B). Liver biopsy specimens were taken before, after 12 months, and at the end of study. Glucose tolerance tests, serum cortisol levels, and adrenocorticotropin-stimulated cortisol secretion were assessed at regular intervals. Bone mass density was measured by dual-energy photon absorptiometry.

RESULTS

Compared with pretreatment values, liver enzyme and immunoglobulin M and G levels decreased significantly in both groups. Improvement in group A was significantly more pronounced (P < 0.05) than in group B. Titers of antimitochondrial antibodies did not change. In group A, the point score of liver histology improved by 30.3%; in group B, it deteriorated by 3.5% (P < 0.001). Changes in bone mineral density after 2 years were -1.747% in group A and -0.983% in group B (P = 0.43). Budesonide had little influence on the hypothalamic-pituitary-adrenal axis. One patient in group A had budesonide-related side effects; in 3 patients in group B, complications of liver disease developed.

CONCLUSIONS

Combination therapy with UDCA and budesonide is superior to UDCA and placebo.

Cerebellar contributions to the perception of temporal cues within the speech and nonspeech domain

A previous study (Ackermann, Gräber, Hertrich, & Daum, 1997) reported impaired phoneme identification in cerebellar disorders, provided that categorization depended on temporal cues. In order to further clarify the underlying mechanism of the observed deficit, the present study performed a discrimination and identification task in cerebellar patients using two-tone sequences of variable pause length. Cerebellar dysfunctions were found to compromise the discrimination of time intervals extending in duration from 10 to 150 ms, a range covering the length of acoustic speech segments. In contrast, categorization of the same stimuli as a "short" or "long pause" turned out to be unimpaired. These findings, along with the data of the previous investigation, indicate, first, that the cerebellum participates in the perceptual processing of speech and nonspeech stimuli and, second, that this organ might act as a back-up mechanism, extending the storage capacities of the "auditory analyzer" extracting temporal cues from acoustic signals.

Temporal and spectral aspects of coarticulation in ataxic dysarthria: an acoustic analysis

In order to analyze the impact of cerebellar disorders on temporal and spectral aspects of coarticulation, 9 individuals with cerebellar dysfunction and 9 controls were asked to produce test sentences comprising a target vowel (V = [a], [i], or [u]) within a schwa-t-V-t-schwa environment. The control speakers were investigated both at their habitual speech tempo and under a slow speaking condition. The squared distances between averaged FFT spectra served as a quantitative estimate of target-induced coarticulation, a method that can be applied to consonants as well as vowels, and which avoids the shortcomings of formant analysis. In order to test the significance of coarticulation effects at the level of individual speakers and to obtain F values as a further measure of the strength of coarticulation, multivariate tests of target effects were performed, with the first 6 principal components derived from the spectra of each speaker. First, inconsistent patterns of anticipatory vowel-to-vowel (W) interactions emerged across individuals, and neither significant group differences nor any effects of speech rate could be detected. The underlying control mechanisms thus seem to be segment-linked subject-specific specifications of the pretarget vowel, uncompromised by cerebellar dysfunction. Second, all participants exhibited highly significant anticipatory [t(h)]-to-vowel (CV) coarticulation. This effect was slightly smaller in the cerebellar group than in the control group, which can be at least partially explained by reduced spectral distances among the 3 target vowels. Speech rate did not influence the CV effects of the control group. As concerns temporal aspects of coarticulation, no significant group differences emerged in terms of length adjustments of the pretarget consonant to the intrinsic duration of the target vowel. Third, ataxic speakers showed a tendency toward enlarged perseverative vowel-to-[t(h)] (VC) and W effects if their slow speech rate was taken into account. Retentive coarticulation turned out to be similar in slow ataxic speakers and in fast-speaking controls. However, significant attenuation of these effects emerged in the latter group under the condition of decreased speech tempo. In summary, these results corroborate the suggestion of different mechanisms of gestural overlap in the temporal domain: Whereas perseverative coarticulation, presumably, reflects biomechanical or motor constraints, anticipation seems to represent higher level phonetic processing.

Phonemic vowel length contrasts in cerebellar disorders

Apraxia of speech and Broca's aphasia both affect voice onset time (VOT) whereas phonemic vowel length distinctions seem to be preserved. Assuming a close cooperation of anterior perisylvian language zones and the cerebellum with respect to speech timing, a similar profile of segment durations must be expected in ataxic dysarthria. In order to test this hypothesis, patients with cerebellar atrophy or cerebellar ischemia were asked to produce sentence utterances including either one of the German lexial items "Rate" (/ra:t(h)e/, 'installment'), "Ratte" (/rat(h)e/, 'rat'), "Gram" (/gra:m/, 'grief'), "Gramm" (/gram/, 'gramm'), "Taten" (/t(h)atn/, 'actions'), or "Daten" (/datn/, 'data'). At the acoustic signal, the duration of the target vowels /a/ and /a:/ as well as the VOT of the word-initial alveolar stops /d/ and /t/ were determined. In addition, a master tape comprising the target words from patients and controls in randomized order was played to three listeners for perceptual evaluation. In accordance with a previous study, first, the cerebellar subjects presented with a reduced categorical separation of the VOT of voiced and unvoiced stop consonants. Second, vowel length distinctions were only compromised in case of the minimal pair "Gram"/"Gramm." In contrast to "Rate"/"Ratte", production of the former lexical items requires coordination of several orofacial structures. Disruption of vowel length contrasts would, thus, depend upon the complexity of the underlying articulatory pattern.

Hemispheric lateralization of the neural encoding of temporal speech features: a whole-head magnetencephalography study

Using a passive oddball design (randomized series of standard [frequent] and deviant [rare] stimuli), the present study investigated the neural encoding of syllables differing in a duration parameter (/da/ = short-lag voice onset time [VOT], /ta/ = long-lag VOT) by means of whole-head magnetencephalography (MEG). Dipolar activities at the level of the supratemporal planes allowed to explain the evoked magnetic fields. The N1m/P2m-complex (magnetic equivalent to the N /P2-wave of the electroencephalogram) in response to standard stimuli showed bilateral symmetric distribution. Furthermore, the latency of P2m significantly depended on VOT. Finally, the mismatch response to the deviant /da/-syllables-which represent in German a very frequent word (English: 'here' or 'there')- evolved significantly earlier in the left hemisphere as compared to the right side. In conclusion, processing speed may be an important aspect of the hemispheric specialization of language.

Role of the striatum and the cerebellum in motor skill acquisition

Motor skill acquisition was investigated in patients with Parkinson's disease (PD) or cerebellar dysfunction using two sensory-guided tracking tasks. The subjects had to learn to track a visual target (a square) on a computer screen by moving a joystick under two different conditions. In the unreversed task, the horizontal target movements were semi-predictable and could be anticipated. In the reversed task, the horizontal movements of a pointer which had to be kept within the target square were mirror-reversed to the joystick movements. PD patients showed intact learning of the semi-predictable task and reduced learning of the mirror-reversed task; patients with cerebellar dysfunction showed the opposite pattern. These findings are discussed in relation to the differential contribution of the cerebellum and the striatum to motor skill acquisition: the cerebellum appears to participate in the implementation of anticipatory movements, whereas the striatum may be critically involved in types of motor learning which require a high degree of internal elaboration.

Dynamic pattern of brain activation during sequencing of word strings evaluated by fMRI

An impaired ability to recite highly automated word strings (e.g., the names of the months of the year) in reverse order concomitant with preserved production of the conventional sequence has been considered a salient sign of frontal lobe dysfunction. Using functional magnetic resonance imaging (fMRI), the spatial and temporal pattern of brain activation during covert performance of these tasks was evaluated in healthy subjects. As compared to the response obtained during forward recitation, re-sequencing of the word string yielded additional activation of the bilateral middle and inferior frontal gyri, the posterior parietal cortex and the left anterior cingulate gyrus. The prefrontal responses are in accordance with the clinical findings referred to. However, the set of activated areas, as a whole, presumably reflects contribution of the various components of the working memory system to the sequencing of word strings. During successive periods of task administration, subjects showed a linear increase of production speed. Analysis of corresponding dynamic changes of regional hemodynamic responses revealed a significant increase at the level of the left inferior parietal cortex and a decrease within the mesial aspect of the left superior frontal gyrus. Presumably, the former finding reflects increasing demands on the phonological short-term memory store, due to faster updating of its content under increased word production rate. Decreasing activation within the superior frontal gyrus might indicate contribution of this area to the initiation of the cognitive processes subserving the sequencing of verbal items. These findings demonstrate the capability of fMRI as a powerful tool for the analysis of dynamic brain activation.

Does the cerebellum contribute to cognitive aspects of speech production? A functional magnetic resonance imaging (fMRI) study in humans

Several positron emission tomography (PET) studies suggest a contribution of the lateral aspects of the right cerebellar hemisphere to higher-level (cognitive) aspects of speech production such as controlled verbal response selection. As an alternative, however, 'inner speech', giving rise to subliminal activity of orofacial and laryngeal muscles, might account for the observed activation effects. Eighteen subjects underwent functional magnetic resonance imaging (fMRI) during continuous silent recitation of the names of the months of the year ('automatic speech'). The right cerebellar hemisphere showed a significantly increased hemodynamic response concomitant with, among others, an asymmetric activation pattern towards the left side at the level of the motor strip. Since highly overlearned word strings, presumably, pose few demands on controlled response selection and since the projections of the right cerebellar hemisphere to the left precentral gyrus participate in motor control, the observed cerebellar activation, thus, seems to be related to the articulatory level of speech production rather than, as suggested by previous PET studies, to cognitive operations.

Dissolution of gallbladder stones with methyl tert-butyl ether and stone recurrence: a European survey

Since there are now several ways to treat symptomatic gallstone disease, one is able to select treatment on the basis of the patient's comfort, the practicability, effectiveness, and side effects of the technique, and the relative costs. In order to assess the present status of contact dissolution with methyl tert-butyl ether with regard to these aspects, the present enquiry reports the data of 21 European hospitals. Eight hundred three patients were selected for contact litholysis of cholesterol gallbladder stones using methyl tert-butyl ether. Percutaneous transhepatic puncture of the gallbladder was performed under x-ray or ultrasound guidance. Dissolution rate, side effects, and treatment times of 268 patients from one single center were compared to those of 535 patients from the other 20 centers. Two hundred sixty-four patients were followed for five years to assess stone recurrence. Physicians were asked how they assessed the expenditure of the method, the discomfort to the patients, and the staffing situation. Patients were asked to indicate their acceptance on an analog scale. Puncture was successful in 761 (94.8%) patients. Prophylactic administration of antibiotics was not necessary. Stones were dissolved in 724 (95.1%) patients. In 315 (43.5%) sludge remained in the gallbladder. The most severe complication was bile leakage, which led 12 (1.6%) patients to have elective cholecystectomy. Toxic injuries due to the ether were not reported. Method-related lethality amounted to 0%, 30-day-lethality to 0.4%. Stone recurrence rate was about 40% in solitary stones and about 70% in multiple stones over five years. Patients with multiple stones developed recurrent stones almost twice as often as those with solitary stones. The probability of stone recurrence in patients with sludge in the gallbladder after catheter removal was not statistically significantly different from those without sludge. Seventy to 90% of the centers found the puncture to be simple and not distressing for patients and the relation between expenditure and therapeutic success to be acceptable. The acceptance of contact litholysis by the patients was excellent. Contact litholysis when applied by an experienced team provides real advantages in the treatment of gallstone disease. The method is technically simple, well accepted by the patients, and can be easily applied in community hospitals. Contact litholysis may be of particular value in patients who are not suitable for anesthesia or surgery.

Auditory perceptual evaluation of rhythm-manipulated and resynthesized sentence utterances obtained from cerebellar patients and normal speakers: A preliminary report

Alterations of the temporal structure of spoken utterances in terms of lengthened acoustic segments and increased syllabic isochrony seem to represent a salient feature of ataxic dysarthria. The present study addresses the question of whether systematic manipulations of the durational aspects of the acoustic speech signal yield an improvement of perceived dysarthric deficits. Different variants of speech rhythm were imposed on sentence utterances obtained from two patients with ataxic dysarthria and two normal control speakers. For the sake of comparability the pitch contours were standardized by means of linearly interpolated stylized versions. The introduced manipulations significantly influenced the ratings of perceived slowness, dysfluency, and rhythmic adequacy. With respect to estimates of overall intelligibility and naturalness, however, ataxic-dysarthric utterances did not benefit from any synthetic changes. By contrast, utterances of normal speakers were rated less intelligible and somewhat more unnatural when resynthesized with an ataxic rhythm. These results indicate that durational factors play a minor role with respect to the overall speech impairment of ataxic speakers.

Categorical speech perception in cerebellar disorders

Keele and Ivry (1991) considered the cerebellum an "internal clock" responsible for temporal computations both in the motor and in the perceptual domain. These authors, therefore, expected that the processing of durational parameters of the perceived acoustic speech signal such as voice onset time (VOT) depends upon the cerebellum as well. However, a preliminary investigation of Ivry and Gopal (1992) revealed unimpaired phoneme-boundary effects in cerebellar patients along a continuum of monosyllabic stimuli with systematically varied VOT (/ba/-/pa/). Since the energy of the aspiration noise provides additional cues for the discrimination of voiced and voiceless stops, the present study used a series of disyllabic stimuli differing in a purely durational parameter. Both controls and patients with unilateral cerebellar lesion identified the endpoints of this continuum in nearly all instances as the counterparts of a minimal pair (Boten, /bo:tn/, "messengers" versus Boden, /bo:dn/, "floor"). Subjects with bilateral pathology of the cerebellum, in contrast, did not show a comparable phoneme-boundary effect. Our data corroborate the hypothesis of the cerebellum as an internal clock and implicate a role of this structure in speech perception.