Biomedical subjects

B E Murdoch

Publications and source records attributed to B E Murdoch.

At least 37 records · Page 2Linked to original sources

PubMed1998

Lip and tongue function in multiple sclerosis: A physiological analysis.

A physiological analysis of the articulatory function of 16 adults with multiple sclerosis (MS) was performed using lip and tongue transduction systems. Sixteen nonneurologically impaired adults, matched for age, gender, and education, served as controls. The MS speakers demonstrated patterns of tongue function that were significantly different from those of the control speakers. Specifically, the MS speakers were found to have significantly reduced tongue strength, endurance, and rate of repetitive movements. In addition, preclinical signs of lingual dysfunction were evident in nondysarthric MS speakers on endurance and rate tasks when compared to control subjects. These physiological findings could account for the perceptual findings of impaired articulation and reduced intelligibility. No lip dysfunction was found on either the physiological or perceptual assessments.

Adult↗

PubMed1998

Effect of oral levodopa treatment on articulatory function in Parkinson's disease: preliminary results.

To quantify lip function in 16 patients with Parkinson's disease, a computerized semiconductor lip pressure transducer system was used prior to subjects being administered oral levodopa and at approximately 0.5 hr, 1.5 hr, and 3.0 hr postmedication. Two blood samples were taken from each subject at varying times during the levodopa dosage interval, and the exact time and dosage of levodopa were noted. Lip function measurements were expressed as percentage changes from baseline and were plotted for each subject against time and levodopa concentrations to determine the effects of levodopa therapy on articulatory function. The results supported the effectiveness of levodopa therapy in improving lip function. In particular, lip pressures recorded during both speech and nonspeech tasks tended to improve after levodopa administration, the lip measures improving somewhat in parallel with the rise and fall of blood plasma levodopa concentrations. Evidence of a hysteresis effect was noted.

Aged↗

PubMed1997

Variability in upper motor neurone-type dysarthria: an examination of five cases with dysarthria following cerebrovascular accident.

The degree of diversity in the nature and extent of the physiological deficits which occur in subjects with dysarthria with similar neurological damage is demonstrated through the individual assessment profiles of five subjects with dysarthria following upper motor neurone (UMN) damage. The perceptual profiles of each subject were compiled using perceptual ratings of deviant speech parameters, intelligibility ratings from the Assessment of Intelligibility of Dysarthric Speech (ASSIDS), and perceptual judgements of subsystem function determined from the Frenchay Dysarthria Assessment (FDA). For each individual, the perceptual profile of their speech impairments was compared and contrasted with the objective results of spirometric and kinematic assessments of respiratory function aerodynamic and electroglottographic evaluations of laryngeal function, pressure and strain gauge evaluations of articulatory function, and nasal accelerometric assessments of nasality. The outcomes of the individual perceptual and physiological profiles are discussed with respect to the presence of differential subsystem impairments both within each subject and between subjects with similar underlying pathophysiological deficits. The importance of interpreting the instrumental findings with respect to the interdependency of each of the motor speech subsystems, the limitations of perceptual assessments, and the advantages of utilising both perceptual and physiological analyses in the process of identifying treatment goals is discussed.

Aged↗

PubMed1996

The effect of the presentation of visual and auditory stimuli on the breathing patterns of two girls with Rett syndrome.

The respiration patterns of individuals with Rett syndrome are known to be dysrhythmic during wakefulness, suggesting cortical involvement of brainstem respiratory control. To investigate this involvement further, the waking breathing patterns of two girls with Rett syndrome were analysed during three phases: a quiet phase, and two phases during which visual and auditory stimuli were presented in controlled intervals. Differences were noted between the two subjects' respiratory patterns in both the quiet and stimulation phases. The usual quiet respiration patterns became more dysrhythmic for both girls during stimulation, with shortened breathing cycles and lengthened apnoeic pauses for the one subject, and increased numbers of apnoeic pauses and shallower breaths for the other. These results suggest that the cyclical brainstem control of breathing patterns in Rett syndrome may be subject to disruption as a result of cortical influences, including arousal subsequent to the engagement of attention.

Acoustic Stimulation↗

PubMed1995

Disorders of nasality in subjects with upper motor neuron type dysarthria following cerebrovascular accident.

The nasality of 19 subjects with upper motor neuron (UMN) damage following cerebrovascular accident (CVA), and 19 control subjects matched for age and sex, was investigated using both perceptual judgements of nasality and a modified version of the nasal accelerometric procedure described by Horii (1980). Nasality indices were calculated for each subject during the production of a series of nasal and non-nasal sounds, words, and sentences. Statistical comparison of the two groups revealed that the CVA subjects had significantly higher nasality indices on the production of nonnasal speech tasks than the controls. No significant difference was noted between the two groups on nasal tasks. Individual case by case examination of the accelerometer data confirmed the presence of hypernasality in 7 of the 19 CVA subjects. In contrast to the instrumental findings, the results of the perceptual judgements of nasality identified the presence of hypernasality, hyponasality, and normal nasal resonance within the CVA group.

Aged↗

PubMed1995

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.

Adult↗

PubMed1995

Variability in the perceptual and physiological features of dysarthria following severe closed head injury: an examination of five cases.

The perceptual and physiological features of the dysarthric speech of five severely closed-head-injured (CHI) subjects were examined in a case-by-case analysis. The five male CHI subjects included in the study were selected to reflect the range of severity and types of dysarthria evident in the CHI population. The perceptual profiles of each subject consisted of the findings of a perceptual speech analysis, the Frenchay Dysarthria Assessment (FDA) and the Assessment of the Intelligibility of Dysarthric Speakers (ASSIDS). The subjects' physiological profiles included the results of instrumental assessments of the respiratory, laryngeal, velopharyngeal and articulatory subsystems of the speech-production mechanism. The case studies highlighted the variability among the individual subjects with respect to the location, physiological nature, and severity of impairment in their speech-production mechanisms. In addition, the interdependence of the various speech subsystems in determining speech outcome, the presence of differential subsystem impairment in dysarthria following CHI, and the varied therapeutic requirements of the individual subjects were identified. Clinically, the case studies highlighted the importance of developing individual treatment programmes based on comprehensive perceptual and physiological evaluations of the speech mechanism in each CHI subject with dysarthric speech.

Adult↗

PubMed1995

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.

Child↗

PubMed1995

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.

Aged↗

PubMed1994

The effect of repeated prime-target presentation in manipulating attention-induced priming in persons with dementia of the Alzheimer's type.

The present experiment manipulated attention-induced semantic priming in seven persons with dementia of the Alzheimer's type (DAT) and 16 healthy aged controls in a word-nonword lexical decision task by means of repeated prime-target presentations. The experimental paradigm allowed for the simultaneous comparison of automatic processing and attention-induced strategic processing. The results showed that both the healthy aged subjects and the subjects with DAT demonstrated semantic facilitation in the automatic processing of information. The two groups differed, however, on the attention-induced component of the task. The control subjects consciously generated a strategic response bias favoring the real word targets and thus used their processing of the prime to induce an expectancy about the following target. The DAT subjects showed no such attention-dependent expectancy, a deficit which is most probably related to the general cognitive impairments which are a hallmark of the disease.

Aged↗

PubMed1994

Speech disorders in children treated for posterior fossa tumours: ataxic and developmental features.

The oromotor and speech abilities of 19 children (14 boys and five girls) who had been treated for posterior fossa tumour were evaluated using three assessment procedures. All subjects completed the Frenchay Dysarthria Assessment and the Fisher-Logemann Test of Articulation Competence. Perceptual analyses were also performed on the subjects' connected speech samples. Based on the three assessment procedures, 11 of the 19 tumour subjects were judged to be speech disordered. The 11 speech-disordered subjects were then compared to a control group matched for age and sex to determine the nature and severity of speech abnormalities which may occur subsequent to the treatment of posterior fossa tumour in childhood. Both developmental and dysarthric features were identified in the speech of the 11 tumour subjects. The deviant speech characteristics exhibited by the tumour subjects included imprecise consonants, excess stress and reduced intelligibility, as well as the retention of developmental phonological processes. These features are described in detail and discussed with reference to descriptive studies of adult dysarthria. An interaction between acquired and developmental disorders of speech is proposed.

Adolescent↗

PubMed1993

Chronic aphasia subsequent to striato-capsular and thalamic lesions in the left hemisphere.

The language abilities of a group of seven chronic aphasics with vascular lesions centered on the striato-capsular region and thalamus of the left hemisphere were described. A range of severity and types of chronic language disorder were documented through assessment using a battery of standardized language tests. The most common language disorder documented was a naming impairment of varying degrees of severity, exhibited by six of the seven cases. The majority of subjects made predominantly semantic errors in the naming task; however, each subject produced a variety of error types and there was no pattern of errors characteristic of the group. The language data obtained were used to evaluate previously developed models of the role of the subcortical structures in naming functions.

Adult↗

PubMed1993

Speech breathing in young adults: effect of body type.

Chest wall kinematic records were obtained from 60 healthy young adults aged 18 to 23 years using a strain-gauge belt pneumograph transduction system. Recordings were taken with the subjects seated in an upright position for measurement of general respiratory function and speech breathing. The 30 males and 30 females also underwent analysis of body type and spirometric assessment. The present study aimed to investigate normative variations in speech breathing kinematics as a function of body type. Measurements of lung volume levels were referenced to two kinematic respiratory points (the 0% limit and resting-end expiratory level) and relative volume displacement of the rib cage and abdomen. Various other assessments of connected speech were analyzed for each subject. Results gathered from four speech tasks (vowel prolongation, syllable repetition, counting, and reading) indicated that an analysis of the three major subdivisions of body type (endomorphy, mesomorphy, ectomorphy) did not show any between-group differences. Further analysis of six subdivisions from the three major subdivisions of body type groups showed few between-group differences. The present investigation provides clinicians and researchers with a comprehensive analysis of the speech breathing characteristics of the young adult population. The need for comparative studies and research into the different methods of assessing chest wall kinematic behavior during speech breathing is highlighted.

Adolescent↗

PubMed1993

Acoustic neuroma and non-tumour retrocochlear patients: audiological features.

Seventeen surgically confirmed acoustic neuroma subjects and seventeen radiologically confirmed non-tumour subjects with retrocochlear pathology of unknown aetiology were selected to investigate retrospectively the diagnostic yield of basic audiological test procedures. Puretone audiometry, tympanometry, reflexometry and auditory brainstem response audiometry were used in the identification of acoustic neuromas versus non-tumour retrocochlear disorders. All subjects had been referred originally for neuroaudiological assessment because of suspected acoustic neuroma and had been found to have a range of abnormal ABR findings consistent with retrocochlear pathology. Detailed retrospective analysis of audiological results following surgical and radiological classification showed subject similarities for most parameters of the individual audiological tests for both acoustic neuroma and non-tumour groups. A significant difference was noted, however, between the two clinical populations for the ABR Wave V absolute interaural latency difference parameter.

Acoustic Impedance Tests↗

PubMed1993

ABR latency-intensity function abnormality in the early detection of a cerebellopontine angle tumour: a case study.

A case is presented of a 27-year-old male subject with a cerebellopontine angle tumour which was provisionally diagnosed on the basis of the ABR latency-intensity function findings and later confirmed by MRI. The patient initially presented with decreased hearing sensitivity, tinnitus and dizziness. The findings of neuroaudiological assessments and radiological examinations are described. The importance of the neuroaudiological test battery, in particular the ABR latency-intensity function, in this case is discussed; and the need for its inclusion for earlier detection and diagnosis of cerebellopontine angle tumours emphasized.

Adult↗

PubMed1991

Closed-head-injured children's performance on narrative tasks.

Stories were elicited from a group of 20 closed-head-injured children. Story grammar and intersentential cohesion were examined. Performance of the head-injured children was compared to that of a group of nonneurologically impaired accident victims matched for age, sex, and socioeconomic status. No significant differences were found between the performance of the closed-head-injured children and the matched controls on any of the measures of narrative ability applied to the elicited narratives.

Adolescent↗

PubMed1991

Respiratory kinematics in speakers with cerebellar disease.

The respiratory abilities of a group of 12 speech disordered subjects with cerebellar disease were assessed using both spirometric and kinematic techniques and compared to those of a group of 12 non-neurologically impaired controls matched for age and gender. Results of the spirometric assessment showed that although all of the cerebellar-diseased subjects had normal total lung capacities, almost half had vital capacities below normal limits. All except 1 of the cerebellar-diseased subjects exhibited irregularities in their chest wall movements while performing sustained vowel and syllable repetition tasks. Over half of the cerebellar-diseased subjects also displayed similar irregularities when reading and conversing. The same irregularities were not present in the chest wall movements exhibited by the control subjects suggesting that their presence was caused by the cerebellar disease. Results are discussed in terms of the effects of cerebellar disease on neuromuscular function.

Adult↗

PubMed1990

Automatic and volitional semantic processing in aphasia.

The present study investigated the status of semantic information in aphasia by comparing the performances of aphasic and nonaphasic subjects on two tasks: an automatic semantic facilitation task and a volitional task of relatedness judgment. Both the aphasic and nonaphasic groups evidenced a semantic facilitation effect, in an on-line task of semantic processing. However, those aphasics with severe comprehension and naming disturbances (termed low comprehension aphasics) demonstrated considerable difficulty in judging the relatedness between a pictured object and members of that object's semantic field, the severity of the impairment being greater for those pictures that the low comprehension aphasics were unable to name. The pattern of results can best be explained by supposing the structural integrity of the store of semantic information in aphasia, and in particular in low comprehension aphasia: information that is retrieved and manipulated in judgment-mediated tasks with considerable difficulty.

Adult↗