Peter D. Stokes

Impaired tongue strength and endurance in developmental verbal dyspraxia: a physiological analysis

Tongue strength and endurance measures were obtained from six children with developmental verbal dyspraxia (DVD) aged between 5;6 years and 11;5 years and compared to those achieved by six normal speaking controls matched for age and sex. The instrument for measuring tongue strength comprised an air-filled soft rubber bulb connected to a pressure transducer. The results indicated that the DVD group had weaker lingual musculature than the controls. In addition the DVD subjects exhibited significantly reduced tongue strength endurance compared with the controls. Overall the findings support the hypothesis that a motor impairment forms at least part of the basis of DVD and may be indicative of the presence of a concomitant dysarthria in children with DVD, or may reflect an underspecification of the motor programme. The need for revision of contemporary taxonomies relating to childhood motor speech disorders is discussed.

Lip function in subjects with upper motor neuron type dysarthria following cerebrovascular accidents

The lip function of 16 speakers with upper motor neuron damage following cerebrovascular accident (CVA), was investigated using instrumental measures. Sixteen, non-neurologically impaired adults matched for age and sex served as controls. The results of the instrumental investigations revealed that the CVA speakers had patterns of lip function that were significantly different from the control speakers. Specifically, on maximum force tasks, the CVA speakers were found to produce significantly lower maximum lip force values. Maximum rate of attempts at lip movement was also slower in the CVA speakers. In addition, the instrumental investigation revealed that the CVA speakers demonstrated a significant decline in pressure over the course of the task involving 10 attempts at maximum lip force. In contrast, the control speakers maintained a consistent level of force throughout the 10 repetitions/attempts. Overall, the findings suggest that the CVA speakers have deficits in maximum lip force, endurance of lip strength and rate of lip movements. Correlations conducted between instrumental measures of maximum lip strength and the perceptual ratings of overall intelligibility, precision of consonants, precision of vowels and length of phonemes revealed no significant relationship.

A physiological analysis of articulatory dysfunction in dysarthric speakers following severe closed-head injury

A physiological analysis of the lip and tongue function of a group of 18 severely closed-head injured (CHI) subjects was performed using lip and tongue force transduction systems. Lip and tongue strength, endurance and rate of repetitive movements were assessed on four non-speech tasks: maximum strength, sustained maximum strength, repetition of 10 maximum strength compressions, and maximum repetition rate. The values recorded were compared to those achieved by a group of 18 non-neurologically impaired subjects, matched for age and sex, who served as the controls. The results of the study indicated that the CHI subjects demonstrated a significant impairment of lip and tongue function based on strength, endurance and rate of repetitive movements, compared to the controls. While lip function was found to be significantly impaired on several measures of strength and endurance, tongue function was noted to be more severely compromised. The CHI subjects were found to exhibit a significantly reduced rate of repetitive movements of the lips and tongue. The results are discussed in relation to the effects of CHI on neuromuscular function and differential subsystem impairment in dysarthria. The clinical implications of these findings are also discussed in relation to the treatment of articulatory disturbances following severe CHI.

Hypernasality in Dysarthric Speakers Following Severe Closed Head-Injury - a Perceptual and Instrumental Analysis

Hypernasality in the dysarthric speech of 20 severely closed-head-injured (CHI) subjects was investigated using both perceptual and instrumental techniques. A perceptual analysis of the speech of the CHI subjects was performed using a four-point rating scale for hypernasality. Instrumental assessment was carried out using a computerized accelerometric technique yielding a nasal coupling index. Results revealed a high incidence of perceived hypernasality (95%) in the speech of subjects in the CHI group. More than half of these subjects exhibited hypernasality of speech to a moderate to severe degree. When compared with a control group matched for age and sex the severely CHI subjects were perceived as being significantly more hypernasal. Instrumental assessment revealed that the functioning of the velopharyngeal valve in the group of CHI subjects was significantly impaired compared to the control group. The study highlighted the need to evaluate the perceptual and instrumental assessment results for the severely CHI subjects on an individual basis. The clinical implications of these findings are discussed.

Abnormal patterns of speech breathing in dysarthric speakers following severe closed head injury

The respiratory abilities of a group of 20 subjects with a speech disorder resulting from severe closed head injury (CHI) were assessed using both spirometric and kinematic techniques and compared with those of a group of 20 non-neurologically impaired controls matched for age and gender. Results of the spirometric assessment showed that the CHI subjects as a group had lower vital capacities and lower forced expiratory volumes 1 second than the controls. Kinematic assessment also showed that the CHI subjects had problems co-ordinating the action of the rib-cage and abdomen when carrying out speech tasks such as vowel prolongations, syllable repetitions and reading. Results are discussed in terms of the effects of CHI on neuromuscular function.

Lip and tongue function in children with developmental speech disorders: A preliminary investigation

Four children with developmental verbal dyspraxia (DVD), and three children with inconsistent deviant phonological disorder were compared to age-matched control children on measures of tongue strength and endurance and lip movement. The instrument for measuring tongue strength was composed of an air-filled soft rubber bulb connected to a pressure transducer. Measurements of lip movement during speech and non-speech tasks were taken from a video-recording of the childs mouth, recorded using a Perspex grid overlay. The results indicated that the DVD subjects were poorer than the control children on all measures of tongue strength and endurance. While the inconsistent deviant children performed similarly to age-matched controls on the maximum tongue strength task, their performance on endurance and repetitive tasks fell between that of the DVD and control groups. The preliminary lip movement analysis suggested some deficit in control of lip movement for the DVD and inconsistent subjects. Overall the findings support the hypothesis that children with DVD and those with inconsistent deviant phonology have some form of motor impairment. The differential performance of the two subject groups on tongue strength and endurance tasks is in accordance with the hypothesis that DVD and inconsistent deviant phonology are distinct subgroups of developmental speech disorders. The need for further physiological investigation of the oro-motor skills of speech-impaired children is discussed.

Quantitative analysis of the speed and accuracy of tongue movements in dysarthria subsequent to traumatic brain injury using electromagnetic articulography

It has been recognised that in order to study the displacement, timing and co-ordination of articulatory components (i.e., tongue. lips, jaw) in speech production it is desirable to obtain high-resolution movement data on multiple structures inside and outside the vocal tract. Until recently, with the exception of X-ray techniques such as cineradiography, the study 0. speech movements has been hindered by the inaccessibility of the oral cavity during speech. X-ray techniques are generally not used because of unacceptable radiation exposure. The aim of the present study was to demonstrate the use of a new physiological device, the electromagnetic articulograph, for assessing articulatory dysfunction subsequent to traumatic brain injury. The components of the device together with the measuring principle are described and data collected from a single case presented. A 19 year-old male who exhibited dysarthria subsequent to a traumatic brain injury was fitted wit 2 the electromagnetic articulograph (Carstens AG-100) and a kinematic analysis of his tongue movements during production of the lingual consonants it, s, k/ within single syllable words was performed. Examination of kinematic parameters including movemmt trajectories, velocity, and acceleration revealed differences in the speed and accuracy of his tongue movements compared to those produced by a non-neurologically impaired adult male. It was concluded that the articulograph is a useful device for diagnosing speed and accuracy disorders in tongue movements during speech and that the device has potential for incorporation into physiologically based rehabilitation programs as a real-time biofeedback instrument.Dysfunction of the articulatory subsystem (i.c.. the lips, tongue, and jaw) has bccn identified as a major contributor to the reduction in speech intelligibility experienced by a high proportion of people with multiple sclerosis (MS). In particular. consonant imprecision has been reported to be the articulatory deficit that contributes most to variations in overall intelligibility of MS speakers. Electropalatography(EPG) IS an instrurncntal technique that visually documents the location and timing of tongue-topalatc contacts during speech. Although such a technique would be valuablc in objectively assessing the articulatory disturbances exhibited by individuals with dysarthria ia motor speech disorder) associated with MS, to-date no such study ha< been reported. The aim of the present study was to use EPG to assess tongue-to-palate contact patterns and articulatory timing in patients with dysarthria associated with MS. A dysarthric participant with a diagnosis of definite MS was fitted with an acrylic EPG palate (Reading EPG.?) and asked to read aloud a list of single syllable words which contained lingual consonants in the word-initial position and in consonant clusters. Each mord was repeated five times. The EPG palate was specifically moulded to tit the participants hard palate and contained 62 electrodes that detected the tongue contacts. A non-neurologically impaired participant matched for age and sex servcd as a control. The results of the study revealed that the tongue-to-palate contacts produced by the participant with MS varied from those produced by the control in a number of ways in regard to spatial configurations and timing characteristics exhibited. The rcsults arc discussed in relation to the neuropathophysiological effects of MS on speech production. The potcntial use of EPG in programs for treating speech disorders associated with MS will be highlightcd.No single standardised version (including standardised stimuli and administration instructions) of the Stroop Test (Stroop, 1935) exists. Instead, numerous versions of this task, with varying stimuli, administration guides and scoring procedures are used both clinically and in research settings. While several adaptations of Stroop-type have been created no one type has gained prominence either clinically or experimentally. When the Golden Stroop appeared commercially as a package measure (Golden, 1978) the administration guide suggested that items could be read either in columns or rows. Some research suggesting that reading down in columns rather than across rows reduced the degree to which reading skills influenced final scores was cited. An adaptation of the traditional Stroop test, the California Older Adult Stroop Test (COAST; Pachana, Marcopulos, Yoash-Gantz, and Thompson, 1995), has been developed specifically for use with a geriatric population, utilising larger typeface, fewer items (50) per trial, and more easily distinguished colours (red, yellow, and green). These two tests were compared in terms of administration instructions, rate of errors, and their acceptability to head-injured older adults. Administration was vulnerable to confounds of both speed and err,x rate when instructions varied in the Golden version. Furthermore, blue- green colour-,,onfusion was a significant problem for older head-injured adults on the Golden Stroop, mirroring previous results for normal and diabetic older adult populations as well as Alzheimer patients (Pachana, Marcopulos, Yoash-Gantz, and Thompson, 1995, 1997).