Justine V. Goozee

Challenging the dual assumption of the 'always/already' autonomous student and effective supervisor

Postgraduate supervision, until recently, was regarded as an extension of research rather than as a form of teaching. Research students were assumed to be ‘always/already’ autonomous scholars at the beginning of their candidature. So too, postgraduate supervisors were assumed to be ‘always/already’ effective at supervising once they had endured the process themselves. Currently, postgraduate supervision is regarded as a form of mentoring, where students gradually master appropriate disciplinary research knowledge. Yet, supervisors also wrestle with the contradictory role of disciplinary gatekeeper. As a result, the ‘always/already’ autonomous student and effective supervisor pair remains a strong underlying assumption in supervision pedagogy. This article explores how Justine, a new supervisor in the Health Sciences, and Catherine, an academic developer and supervisor in the Humanities/Higher Education, hope to contribute to this debate by developing a collaborative approach to enhancing research students’ critical analysis and independent learning abilities.

Physiological assessment of tongue function in dysarthria following traumatic brain injury

A tongue pressure transducer system was used to assess tongue strength, endurance, fine pressure control and rate of repetitive movement in a group of 20 individuals, aged 17 to 60 years, with dysarthria following severe traumatic brain injury (TBI). Comparison of the TBI groups results against data obtained from a group of 20 age and sex matched control subjects revealed reductions in tongue endurance and rate of repetitive movement. Tongue strength and fine pressure control, however, were found not to differ significantly from the control group. Pearsons product-moment correlations indicated there to be only weak correlations between the physiological nonspeech tongue parameters and the deviant perceptual articulatory features exhibited by the TBI group. Further analysis of the results on an individual subject basis revealed no clear relationships between the physiological and perceptual parameters suggesting that the TBI subjects may have been compensating in different ways for the physiological impairments.

The effects of age and gender on laryngeal aerodynamics

A computerized airflow/air pressure analysis system, the Aerophone II Model 6800 (Kay Elemetrics Corp.), was used to assess the effects of age and gender on laryngeal aerodynamics. A sample of 56 male and 53 female normal speaking subjects was divided into six age groups (20-30; 31-40; 41-50; 51-60; 61-70 and 71-80 years). The laryngeal aerodynamic parameters measured included phonatory (mean) flow rate, estimated subglottal pressure, laryngeal airway resistance, phonatory sound pressure level, phonatory power, and phonatory efficiency. Most comfortable phonation, vocal efficiency, and running speech tasks were used to collect the aerodynamic data. Comfortable pitch and loudness levels were used for each of these tasks. Age and gender effects were found for a number of the phonatory (mean) flow rate and phonatory sound pressure level values. Results failed, however, to indicate age or gender effects for the estimated subglottal pressure, laryngeal airway resistance, phonatory power and phonatory efficiency parameters. High intersubject variability was found for the phonatory flow rate, laryngeal airway resistance, phonatory power and phonatory efficiency values. Estimated subglottal pressure values, however, appeared to vary the least among subjects. The results are discussed with respect to factors that might influence laryngeal aerodynamics, such as underlying laryngeal anatomical and physiological age-related changes and gender-related differences. The clinical implications of the findings for the assessment and treatment of individuals with voice disorders using the Aerophone II are also discussed.

Lingual kinematic strategies used to increase speech rate: comparison between younger and older adults.

The primary objective of this study was to assess the lingual kinematic strategies used by younger and older adults to increase rate of speech. It was hypothesised that the strategies used by the older adults would differ from the young adults either as a direct result of, or in response to a need to compensate for, age‐related changes in the tongue. Electromagnetic articulography was used to examine the tongue movements of eight young (M = 26.7 years) and eight older (M = 67.1 years) females during repetitions of /ta/ and /ka/ at a controlled moderate rate and then as fast as possible. The younger and older adults were found to significantly reduce consonant durations and increase syllable repetition rate by similar proportions. To achieve these reduced durations both groups appeared to use the same strategy, that of reducing the distances travelled by the tongue. Further comparisons at each rate, however, suggested a speed‐accuracy trade‐off and increased speech monitoring in the older adults. The results may assist in differentiating articulatory changes associated with normal aging from pathological changes found in disorders that affect the older population.

Electromagnetic articulography assessment of articulatory function in adults with dysarthria following traumatic brain injury

Primary objective: To explore articulatory kinematic differences between normal and dysarthric speakers post-traumatic brain injury (TBI) during syllable and sentence productions. Research design: A comparison between the control, mild (MTBI) and severe TBI groups for all measured kinematic parameters was carried out using the Kruskal Wallis test. Methods and procedures: Ten participants with a severe TBI and six post-MTBI formed the experimental group. The control group consisted of 14 age and sex matched non-neurologically impaired speakers. Articulatory kinematic profiles for the three groups were obtained using the Electromagnetic Articulograph (EMA) while repeating sentence and syllable embedded /t/ and /k/ productions at a habitual rate and loudness level. Main outcomes and results: Significant differences between the severe TBI and control group were identified only for the release phase of the /t/ sentence productions wherein an increase in mean maximum acceleration was observed for the severe TBI group. Conclusions: While a simple syllable repetition task at a moderate rate was unable to differentiate the three groups, a complex sentence production task precipitated an increase in mean maximum acceleration which may be indicative of increased articulatory effort and impaired speech motor control even at a convenient rate for the severe group.

EMA analysis of tongue function in children with dysarthria following traumatic brain injury.

Primary objective: To investigate the speed and accuracy of tongue movements exhibited by a sample of children with dysarthria following severe traumatic brain injury (TBI) during speech using electromagnetic articulography (EMA). Methods and procedures: Four children, aged between 12.75-17.17 years with dysarthria following TBI, were assessed using the AG-100 electromagnetic articulography system (Carstens Medizinelektronik). The movement trajectories of receiver coils affixed to each childs tongue were examined during consonant productions, together with a range of quantitative kinematic parameters. The childrens results were individually compared against the mean values obtained by a group of eight control children (mean age of 14.67 years, SD 1.60). Main outcomes and results: All four TBI children were perceived to exhibit reduced rates of speech and increased word durations. Objective EMA analysis revealed that two of the TBI children exhibited significantly longer consonant durations compared to the control group, resulting from different underlying mechanisms relating to speed generation capabilities and distances travelled. The other two TBI children did not exhibit increased initial consonant movement durations, suggesting that the vowels and/or final consonants may have been contributing to the increased word durations. Conclusions and clinical implications: The finding of different underlying articulatory kinematic profiles has important implications for the treatment of speech rate disturbances in children with dysarthria following TBI.

EMA assessment of tongue–jaw co-ordination during speech in dysarthria following traumatic brain injury

Primary objective: To investigate the spatio-timing aspects of tongue–jaw co-ordination during speech in individuals with traumatic brain injury (TBI). It was hypothesized that both timing and spatial co-ordination would be affected by TBI. Research design: A group comparison design wherein Mann-Whitney U-tests were used to compare non-neurologically impaired individuals with individuals with TBI. Methods and procedures: Nine non-neurologically impaired adults and nine adults with TBI were involved in the study. Electromagnetic articulography (EMA) was used to track tongue and jaw movement during /t/ and /k/, embedded in sentence and syllable stimuli. Main outcomes and results: Analysis of group data did not reveal a significant difference in spatio-timing tongue–jaw co-ordination between the control group and TBI group. On an individual basis, a proportion of individuals with TBI differed from non-neurologically impaired participants with regard to articulatory order and percentage of jaw contribution to /t/. Conclusions: EMA assessment results supported perceptual data; those adults who presented with severe articulatory disturbances exhibited the most deviant spatio-timing tongue–jaw co-ordination patterns. This finding could provide a new and specific direction for treatment, directed at combined movement patterns.

Effects of speaking rate on EMA-derived lingual kinematics: a preliminary investigation

Electromagnetic articulography (EMA) was used to investigate how tongue movement characteristics (i.e., velocity, acceleration, duration, distance) change with, or indeed affect, increased rates of speech. Eight young adult males repeated /ta/ and /ka/ syllables first at a moderate rate that had been modelled at three syllables per second, and then ‘as fast as possible’. Distance travelled by the tongue appeared to be the principal lingual kinematic feature manipulated by the group of speakers in producing increased syllable repetition rates, with velocity found to increase, decrease or remain unchanged. Acceleration remained unchanged, except in the case of increased velocity. One participant formed an exception in terms of manipulating distance by exhibiting marginally increased lingual velocities rather than distance changes. This preliminary study serves to direct future EMA‐based studies of speech rate control as to the speech tasks that should be employed and the possible underlying anatomical and acoustic bases or constraints that could possibly influence the kinematic strategies employed to increase speech rate.

Electropalatographic (EPG) assessment of tongue-to-palate contacts in dysarthric speakers following TBI

The aim of the investigation was to compare EPG‐derived spatial and timing measures between a group of 11 dysarthric individuals post‐severe TBI and 10 age‐ and sex‐matched neurologically non‐impaired individuals. Participants of the TBI group were diagnosed with dysarthria ranging from mild‐to‐moderate–severe dysarthria. Each participant from the TBI and comparison group was fitted with a custom‐made artificial acrylic palate that recorded lingual palatal contact during target consonant production in sentence‐ and syllable‐repetition tasks at a habitual rate and loudness level. Analysis of temporal parameters between the comparison and TBI groups revealed prolonged durations of the various phases of consonant production, which were attributed to articulatory slowness, impaired speech motor control, impaired accuracy, and impaired coordination of articulatory movements in the dysarthric speakers post‐TBI. For the spatial measurements, quantitative analysis, as well as visual inspection of the tongue‐to‐palate contact diagrams, indicated spatial aberrations in dysarthric speech post‐TBI. Both the spatial and temporal aberrations may have at least partially caused the perceptual judgement of articulatory impairments in the dysarthric speakers.

Temporal features of articulation from childhood to adolescence: An electropalatographic investigation

This study was designed to investigate the development of articulatory timing from mid‐childhood to late adolescence. Productions of sentences containing /t/, /l/, /s/, and /k/ were produced by 48 children and adults (aged 6‐38 years) and captured using the Reading Electropalatography3 (EPG3) system. Mean duration of the sentences and the approach, closure/stable constriction, and release phases of consonant articulation were calculated. In addition, temporal coordination of lingual gestures and the intra‐subject articulatory timing variation were investigated across the ages. Results reveal some distinct differences in duration and temporal coordination of lingual gestures between 6‐ to 7‐year‐olds and mature speakers, with continual refinement of articulatory control indicated into late adolescence. Differences in articulatory stability, in contrast, were not significant. The present findings may form a platform for development of a more descriptive model of motor speech development.