Michael P. Cannito

Outcomes of swallowing rehabilitation in chronic brainstem dysphagia: A retrospective evaluation.

Abstract. This study examines the functional and physiologic outcomes of treatment in a group of 10 patients with chronic dysphagia subsequent to a single brainstem injury. All patients participated in a structured swallowing treatment program at a metropolitan teaching hospital. This program differs from more traditional swallowing treatment by the inclusion of surface electromyography biofeedback as a treatment modality and the completion of 10 hr of direct treatment in the first week of intervention. A retrospective analysis of medical records and patient questionnaires was used to gain information regarding medical history, site of lesion, prior interventions, and patient perception of swallowing recovery. Physiologic change in swallowing treatment, as measured by severity ratings of videofluoroscopic swallowing studies, was demonstrated in nine of 10 patients after 1 week or 10 sessions of treatment. Functional change was measured by diet level tolerance after 1 week of treatment, at 6 months, and again at 1 year posttreatment. Eight of the 10 patients were able to return to full oral intake with termination of gastrostomy tube feedings, whereas two demonstrated no long-term change in functional swallowing. Of the eight who returned to full oral intake, the average duration of tube feedings following treatment until discontinuation was 5.3 months, with a range of 1–12 months. Six patients who returned to oral intake maintained gains in swallowing function, and two patients returned to nonoral nutrition as the result of a new unrelated medical condition.

Disruption of reference in aging

A homogeneous sample of normal adults living in a religious order in a study of age effects on reference as a cohesive device in discourse production and comprehension. Narrative and procedural discourse were examined across various levels of complexity and stimulus/response requirements. Results indicate that significant ambiguity of reference emerges in the younger elderly group (age 64-76) in comparison to the middle-aged group (age 27 to 55), and increases markedly in the older elderly group (age 77-92). Related impairments of comprehension and cognition were also observed. These findings are interpreted to be general features of linguistic variation with advancing age. Communicative consequences of ambiguous reference are discussed.

Cortical Control Mechanisms in Volitional Swallowing: The Bereitschaftspotential

Objective: This research sought to identify a well-defined pre-motor potential, the Bereitschaftspotential (BP), as a manifestation of cortical contribution to the pre-motor planning of volitional swallowing. Methods: EEG data were collected from 20 research participants during volitional execution of swallowing and finger movement tasks. A 5 second pre-movement epoch for each task was triggered on EMG identification of movement onset. A grand average for each task representing approximately 2400 trials across all research participants was derived to compare and contrast morphological features of the derived waveform. Results: Volitional pharyngeal swallowing and finger movement generated similar waveform characteristics of duration and slope; however, statistically significant differences were identified in polarity and in amplitude at four points both early and late in the epoch. Additionally, swallowing produced a pre-motor waveform with a rapid declination of EEG activity in the final 500 msec prior to movement onset. Conclusions: This study demonstrates activation of the supplementary motor cortex preceding the onset of volitional swallowing. However, unlike purely voluntary movements, the volitional pharyngeal swallowing task, as assessed with this methodology, does not appear to recruit the primary motor cortex. Thus engagement of the swallowing response appears to rely on indirect parallel pathways between extrapyramidal cortical motor planning regions and lower motor neurons.

Spastic dysphonia: a continuum disorder.

Recently, two types of spastic dysphonia, adductor and abductor, have been proposed. The literature suggests that patients may be categorized as having one form of the disorder or the other. The present study presents case history and spectrographic data on a patient who evidences vocal characteristics of both disorder types. It is suggested that spastic dysphonia is a disorder involving a harshness-breathiness continuum and is not amenable to strict, binary categorization.

Sentence intelligibility before and after voice treatment in speakers with idiopathic Parkinson's disease.

OBJECTIVES/HYPOTHESIS The purpose of this study was to determine whether sentence intelligibility improves in speakers with idiopathic Parkinsons disease (PD) as a result of Lee Silverman Voice Treatment (LSVT). It was hypothesized that all the speakers would improve following treatment, in association with increased vocal loudness, which was the primary target of the treatment. STUDY DESIGN Prospective study of eight Speakers with PD using a single-blinded, randomized pre-post treatment design, with multiple daily assessments before and after treatment was carried out. Resultant data were corrected for regression to the mean. METHODS Randomized digital recordings of sentences produced by speakers with idiopathic PD before and after the treatment were presented to normal-hearing listeners with equalized intensity at conversational loudness in the presence of pink noise. Percentage of words understood was calculated before and after the treatment. Changes in overall vocal intensity were also analyzed. RESULTS There was a statistically significant group effect from pre-to-post voice treatment; however, there was also significant interaction of treatment with speakers. Six of the speakers with PD improved significantly following voice treatment, one exhibited no change, and one exhibited a decline in sentence intelligibility post-treatment. CONCLUSIONS LSVT yielded significant improvement in sentence intelligibility for most speakers in the study but was not beneficial for two of the speakers despite the fact that they increased their overall vocal loudness.

Modes of vocal variation in Sykes's monkey (Cercopithecus albogularis) squeals.

Acoustic and laryngographic measurements of Sykess monkey (Cercopithecus albogularis) squeals showed that acoustic variation between exemplars was principally due to 4 underlying modes of modification: (Class I) variation in the transfer function produced by articulation, (Class II) variation in F0 produced by inflection, (Class III) variation in turbulence, and (Class IV) variation in the pattern of vibration of laryngeal tissue with large or small surface areas (polyphonic variation). These findings suggest that some modes of variation (Class I, II, and III calls) were due to phonatory and articulatory acts resembling, at a very general level, sound production mechanics used in speech. Acoustic variation in the polyphonic group (Class IV calls) is not evident in speech and was attributed to the possibility of independent and simultaneous vibrations of the vocal lip and the principal component of the vocal folds.

Contextual influences in aphasia: effects of predictive versus nonpredictive narratives

The influence of prior linguistic predictive and nonpredictive context on the comprehension of reversible passive sentences was investigated in 16 adults with aphasia. Eight subjects were classified as fluent and 8 as nonfluent. Subjects were presented with the sentences in isolation and preceded by nonpredictive and predictive contextual paragraphs. The overall results indicated that the subjects benefited significantly from the prior contextual narratives regardless of whether the paragraphs were predictive or nonpredictive. There were no significant differences between the two subject groups. The significant facilitation generated by the nonpredictive context suggests that redundancy of information may play a role in comprehension.

Comprehension and expression of affective sentences in traumatic brain injury

The comprehension and production of affective prosody and facial expression was investigated in subjects with traumatic brain injury and matched normal subjects. Performance on tasks designed to assess the ability to recognise affect in congruous, neutral, and ambiguous sentences and the ability to portray emotions in affectively neutral sentences revealed significant impairments for the subjects with traumatic brain injury. Analysis of correct responses to ambiguous sentences found increased reliance of brain-injured subjects on verbal compared to paralinguistic cues in interpreting the emotion of the sentence. The clinical implications of the findings relative to counselling, compensation strategies, and direct intervention for patients with traumatic brain injury are discussed.

Magnetic resonance imaging findings and correlations in spasmodic dysphonia patients

A sample of 19 spasmodic dysphonia (SD) patients was selected from a larger population of such patients to undergo magnetic resonance imaging (MRI), auditory brain stem response (ABR) testing, speech analysis, and extensive physical examination. Six patients had abnormal spin-echo MRI findings, ranging from infarcts within the basal ganglia to demyelinating lesions within the supralateral angles of the lateral ventricles. A weakly positive correlation was noted between the abnormal MRI findings and an abnormal ABR. The lack of a significant correlation between the MRI findings and other predictors of brain stem and midbrain disease, and the current spatial resolution limitations of MRI, suggest that we are visualizing the associated lesions rather than the actual foci of SD. The range of MRI findings is consistent with the concept that SD is a voice disorder in a heterogeneous patient population.

Perceptual Structure of Adductor Spasmodic Dysphonia and Its Acoustic Correlates

OBJECTIVES To examine the perceptual structure of voice attributes in adductor spasmodic dysphonia (ADSD) before and after botulinum toxin treatment and identify acoustic correlates of underlying perceptual factors. Reliability of perceptual judgments is considered in detail. STUDY DESIGN Pre- and posttreatment trial with comparison to healthy controls, using single-blind randomized listener judgments of voice qualities, as well as retrospective comparison with acoustic measurements. METHODS Oral readings were recorded from 42 ADSD speakers before and after treatment as well as from their age- and sex-matched controls. Experienced judges listened to speech samples and rated attributes of overall voice quality, breathiness, roughness, and brokenness, using computer-implemented visual analog scaling. Data were adjusted for regression to the mean and submitted to principal components factor analysis. Acoustic waveforms, extracted from the reading samples, were analyzed and measurements correlated with perceptual factor scores. RESULTS Four reliable perceptual variables of ADSD voice were effectively reduced to two underlying factors that corresponded to hyperadduction, most strongly associated with roughness, and hypoadduction, most strongly associated with breathiness. After treatment, the hyperadduction factor improved, whereas the hypoadduction factor worsened. Statistically significant (P<0.01) correlations were observed between perceived roughness and four acoustic measures, whereas breathiness correlated with aperiodicity and cepstral peak prominence (CPPs). CONCLUSIONS This study supported a two-factor model of ADSD, suggesting perceptual characterization by both hyperadduction and hypoadduction before and after treatment. Responses of the factors to treatment were consistent with previous research. Correlations among perceptual and acoustic variables suggested that multiple acoustic features contributed to the overall impression of roughness. Although CPPs appears to be a partial correlate of perceived breathiness, a physical basis of this percept remained less clear.