Modulation of spontaneous and volitional swallowing : methodological and behavioural analyses

This research programme was inspired by a desire to understand the neural underpinnings of an interesting patient cohort with an atypical presentation of dysphagia (Huckabee, Lamvik, & Jones, 2014). These patients presented with mis-sequenced, rather than weakened, pharyngeal constriction when swallowing. As a result, they were unable to coordinate streamlined food or liquid transfer from the pharynx into the oesophagus. This cohort gave rise to a series of studies to explore the nature of underlying neural control of swallowing and mis-swallowing, behavioural modulation of volitional and spontaneous swallowing, and methodological limitations of existing diagnostic techniques. A prospective incidence study is currently ongoing to identify specific patient groups who exhibit pharyngeal mis-sequencing and to further explore mechanisms of pharyngeal sequencing itself. This study is evaluating swallowing in patients with dysphagia as a sequela of four brain disorders (n = 100): base of skull surgery, brainstem stroke, cortical stroke and Parkinson’s disease. Manofluoroscopic results from current participants (n = 7) are reported in this thesis. Completion of this project will likely translate immediately to improved patient care and greater scientific understanding of the complex neural control of swallowing. Previous research has documented that pressure and duration of brainstem-generated pharyngeal swallowing can be cortically modulated (Bülow et al., 2001; Fukuoka et al., 2013; Wheeler-Hegland et al., 2008; Witte et al., 2008). But there is a commonly held belief that the sequence of pharyngeal pressure remains constant (Ertekin, 2011). Intensive training was provided to healthy adults (n = 6) to determine if participants can volitionally alter latency of pharyngeal closure, thereby evaluating the capacity for pharyngeal adaptation in a healthy system. Following training, participants were able to reduce temporal separation of peak pressure between the proximal and distal pharyngeal sensors from a baseline median of 188 ms (interquartile range (IQR) = 231 ms) to 68 ms (IQR = 92 ms; p = 0.002). However, there was a contemporaneous reduction in swallowing duration post-training (p = 0.03). Participants may have achieved a reduced peak-to-peak latency through optimizing a reduction in overall swallowing duration, suggesting volitional modulation cannot alter the reflexive pharyngeal sequence to a pathologic level. Sleep has been associated with periods of relative cortical quiescence (Orr, Johnson, & Robinson, 1984), enabling evaluation of volitional and automatic swallowing conditions. Pharyngeal swallowing was analysed with low and high-resolution manometry in healthy participants (n = 20) and patients with dysphagia (n = 3). Results indicated sleep swallows were of lower amplitude than supine awake swallows (p < 0.01), with no significant difference between awake and supine swallows in terms of latency (p = 0.11) or slope (p = 0.73). This contrasts to findings of patients with dysphagia, who presented with a clear pattern of mis-sequenced pressure during sleep, even in the two patients who were able to sequence pressure adequately to enable functional swallowing when awake. This may provide additional data regarding the debate or the role of volition and arousal in swallowing motor control. Advancements in circumferential sensor technology now enable comparison of manometric catheters with similar diameter (2.1 mm unidirectional diameter to 2.75 mm circumferential diameter). Understanding differences in measurement between these two intraluminal pressure measurement devices is critical to explain the variability in normative data collected by similar intraluminal instruments. A comparison of low- and high-resolution manometry found significant differences in measurement of temporal and amplitude characteristics. Further, in-vivo and in-vitro studies were completed with low- and high-resolution manometry, with stable measurement in low-resolution manometry contrasting to unstable high-resolution manometry measurement, varying both between studies (p < 0.01) and within sensors (p < 0.01). Further, this measurement error is not corrected via the standard operating instructions. Topical nasal anaesthetic is used in research and clinical examinations with pharyngeal highresolution manometry and recommended in clinical protocols (Knigge, Thibeault, & McCulloch, 2013). However, it is unclear if desensitizing the nasal mucosa improves procedure tolerability or affects pharyngeal swallowing. Results indicate topical nasal anaesthetic provides no improvement in procedure comfort (p = 0.23), with potential alterations in pharyngeal swallowing as compared to placebo conditions. Lastly, Knigge et al. (2014) provide the only published clinical protocol for analysis of high-resolution manometry spatiotemporal plots using existing system-based technologies (e.g., ManoScan™ high-resolution manometry systems). Results indicate that, following training, intra-rater reliability was 0.99 (range = 0.97 – 1.0; SD = 0.01) while inter-rater reliability was variable across measures (range = 0.11-0.95; SD=0.32). While this will likely have an impact on current best practice, further research is needed to standardize measurement of pharyngeal swallowing using high-resolution manometry. The studies included in this programme of research contribute to shortcomings in the literature regarding best practice in diagnostic methodology and the nature of underlying neural control of pharyngeal swallowing

Growth of orthographic representations in children with LLD [abstract]

Abstract only availableOne aspect of word learning from reading is knowledge of the orthographic representation of a word. Children with language-learning disabilities (LLD) might be expected to have greater difficulties than peers acquiring this aspect of word knowledge. The present study examines these children's incremental growth in orthographic representations of unfamiliar words, following three contextual, story-based exposures to the words. Sixteen participants with LLD, ages 12;8 to 18;10 years, and seven typically developing age-matched peers read two stories containing 16 unfamiliar words, three times each. Following each reading, they completed a checklist task requiring them to write sentences/definitions for or circle any words they believed to be real words. The checklist contained common words, the target unfamiliar words, and orthographically similar nonwords. Descriptively, findings suggested that, following story readings, the children with LLD (a) responded that fewer of the target words, encountered in the stories, were real words, relative to the performance of age-matched participants; and (b) responded that more of the orthographically similar nonwords (foils) were real words, relative to age-matched participants. This pattern of performance was apparent even after the children had read the stories containing the target words multiple times.MU Undergraduate Research Scholars Progra

The Reliability of Pharyngeal High Resolution Manometry with Impedance for Derivation of Measures of Swallowing Function in Healthy Volunteers

Purpose. We evaluated the intra- and interrater agreement and test-retest reliability of analyst derivation of swallow function variables based on repeated high resolution manometry with impedance measurements. Methods. Five subjects swallowed 10×10 mL saline on two occasions one week apart producing a database of 100 swallows. Swallows were repeat-analysed by six observers using software. Swallow variables were indicative of contractility, intrabolus pressure, and flow timing. Results. The average intraclass correlation coefficients (ICC) for intra- and interrater comparisons of all variable means showed substantial to excellent agreement (intrarater ICC 0.85–1.00; mean interrater ICC 0.77–1.00). Test-retest results were less reliable. ICC for test-retest comparisons ranged from slight to excellent depending on the class of variable. Contractility variables differed most in terms of test-retest reliability. Amongst contractility variables, UES basal pressure showed excellent test-retest agreement (mean ICC 0.94), measures of UES postrelaxation contractile pressure showed moderate to substantial test-retest agreement (mean Interrater ICC 0.47–0.67), and test-retest agreement of pharyngeal contractile pressure ranged from slight to substantial (mean Interrater ICC 0.15–0.61). Conclusions. Test-retest reliability of HRIM measures depends on the class of variable. Measures of bolus distension pressure and flow timing appear to be more test-retest reliable than measures of contractility

Effectiveness of resistance training in combination with botulinum toxin-A on hand and arm use in children with cerebral palsy: a pre-post intervention study

Background The aim of this pilot study was to examine the effects of additional resistance training after use of Botulinum Toxin-A (BoNT-A) on the upper limbs in children with cerebral palsy (CP). Methods Ten children with CP (9–17 years) with unilaterally affected upper limbs according to Manual Ability Classification System II were assigned to two intervention groups. One group received BoNT-A treatment (group B), the other BoNT-A plus eight weeks resistance training (group BT). Hand and arm use were evaluated by means of the Melbourne assessment of unilateral upper limb function (Melbourne) and Assisting Hand Assessment (AHA). Measures of muscle strength, muscle tone, and active range of motion were used to assess neuromuscular body function. Measurements were performed before and two and five months after intervention start. Change scores and differences between the groups in such scores were subjected to Mann–Whitney U and Wilcoxon Signed Rank tests, respectively. Results Both groups had very small improvements in AHA and Melbourne two months after BoNT-A injections, without differences between groups. There were significant, or close to significant, short-term treatment effects in favour of group BT for muscle strength in injected muscles (elbow flexion strength, p = .08) and non-injected muscles (elbow extension and supination strength, both p = .05), without concomitant increases in muscle tone. Active supination range improved in both groups, but more so in group BT (p = .09). There were no differences between the groups five months after intervention start. Conclusions Resistance training strengthens non-injected muscles temporarily and may reduce short-term strength loss that results from BoNT-A injections without increasing muscle tone. Moreover, additional resistance training may increase active range of motion to a greater extent than BoNT-A alone. None of the improvements in neuromuscular impairments further augmented use of the hand and arm. Larger clinical trials are needed to establish whether resistance training can counteract strength loss caused by BoNT-A, whether the combination of BoNT-A and resistance training is superior to BoNT-A or resistance training alone in improving active range of motion, and whether increased task-related training is a more effective approach to improve hand and arm use in children with CP

Auditory-perceptual speech outcomes and quality of life after total laryngectomy

Background: Total laryngectomy (TL) results in challenges to communication, airway, and swallowing. Consequently, individuals often report a pronounced impact on quality of life (QOL). After TL, QOL outcomes are typically measured using cancer-specific and discipline-specific scales. Cancer-specific measures investigate the influence of head and neck cancer symptoms on QOL, while discipline-specific scales examine how a specific area (e.g., voice quality) affects QOL. Other common outcome measures after TL include a listener’s impressions of speech intelligibility or acceptability. A few previous studies have shown weak relationships between perceptions of speech intelligibility/acceptability with patient-reported QOL. However, the degree to which these perceptual variables generally influence QOL is largely unknown. Objectives: a) To determine relationships between speech intelligibility, speech acceptability and a patient’s self-reported QOL, and; b) To determine whether relationships are stronger when QOL is measured by a discipline-specific QOL scale (e.g., Voice Handicap Index-10; VHI-10) or a head and neck cancer-specific QOL scale (e.g., University of Washington Quality of Life; UW-QOL)? Methods: Twenty individuals (16 males, 4 females) who underwent TL (n=6 electrolaryngeal speakers; n=12 tracheoesophageal speakers; n=2 esophageal speakers) completed a disease-specific QOL scale (UW-QOL; Hassan & Weymuller, 1993; Rogers et al., 2002) and a discipline-specific QOL scale (VHI-10; Rosen et al., 2004). Individuals recorded 6 sentences of increasing length (5-15 words) from the Sentence Intelligibility Test (SIT; Yorkston et al., 1996) and a reading passage. Twenty-one inexperienced listeners each transcribed 6 sentences for 3 speakers using the SIT protocol. Each speaker’s intelligibility was based on the average score across 3 listeners. Listeners also judged speech acceptability for the 20 speakers using 100 mm visual analog scales. Twenty percent of the samples were repeated to determine intra-rater reliability (r = .71); intraclass correlation coefficients were calculated as a measure of interrater reliability (ICC = .97, speech acceptability). To determine the relationship between speech intelligibility or speech acceptability with QOL (UW-QOL; VHI-10), correlational analyses were performed. Results: Listeners judged tracheoesophageal and esophageal speakers significantly more acceptable than electrolaryngeal speakers (p \u3c .01). Intelligibility and QOL were not significantly differentiated by speaker type. In addition, listeners’ ratings of speech acceptability were only moderately related to intelligibility (r = .41). Relationships were weak to moderate between ratings of speech and QOL scores, with speech acceptability tending to be a stronger predictor of QOL than intelligibility. The speech sub-score on the UW-QOL related most strongly (r = .507) to speech acceptability (see table 1). Conclusions: Alaryngeal speakers exhibited a wide range of speech acceptability and intelligibility, although these dimensions were not strongly related. These results suggest that while listeners may be able to understand an alaryngeal speaker, being understood is not sufficient to render the speech “acceptable” to listeners. Results also revealed that listeners’ judgments of speech are not necessarily predictive of the speakers’ own perceptions of health-related or voice-related QOL. Overall, results suggest that listener-rated and patient-reported measures are complimentary after TL