Frequency Transmission of Oscillation from External Whole-Body Vibration Platform to the Larynx.

PURPOSE: This study investigates (1) the presence of frequency transmission of oscillation from an external whole-body vibration (WBV) platform to the larynx; and (2) the factors that influence this frequency transmission. METHODS: Thirty participants (mean age=22.3years) with normal voice were exposed to four frequency-intensity levels of WBV (10 Hz-10%, 10 Hz-20%, 20 Hz-10%, 20 Hz-20%) and were instructed to produce the natural vowel /a/ three times during each WBV setting. The frequency was extracted from the middle 1-second of each electroglottographic (EGG) signal after passing through a Hann band filter with a range of 6-24 Hz. Linear mixed-effects models were applied to determine the factors that influenced the absolute deviation of the frequency transmission. RESULTS: All participants exhibit an extracted EGG frequency that aligns with the external WBV frequency, deviating by - 0.6 to 1.2 Hz. The absolute deviation of WBV frequency transmission is consistent for both sexes across various WBV settings, except the 10 Hz-10% setting where men tend to exhibit significantly higher deviations (P = 0.018). CONCLUSION: Oscillations at a specific frequency are transmitted from an external WBV platform to the larynx. This study proposes the use of a "spring" system to investigate the effect of WBV on the larynx, and recommends further research to explore the potential of WBV in managing voice disorders.

A longitudinal study of the SF-36 version 2 in Friedreich ataxia.

OBJECTIVES: The Medical Outcomes Study 36 item Short-Form Health Survey (SF-36) is one of the most commonly used patient reported outcome measure. This study aimed to examine the relationship between SF-36 version 2 (SF-36V2) summary scores and Friedreich ataxia (FRDA) clinical characteristics, and to investigate the responsiveness of the scale, in comparison with the Friedreich Ataxia Rating Scale (FARS), over 1, 2 and 3 years. MATERIALS AND METHODS: Descriptive statistics were used to examine the characteristics of the cohort at baseline and years 1, 2 and 3. Correlations between FRDA clinical characteristics and SF-36V2 summary scores were reported. Responsiveness was measured using paired t tests. RESULTS: We found significant correlations between the physical component summary (PCS) of the SF-36V2 and various FRDA clinical parameters but none for the mental component summary. No significant changes in the SF-36V2 were seen over 1 or 2 years; however, PCS scores at Year 3 were significantly lower than at baseline (-3.3, SD [7.6], P=.01). FARS scores were found to be significantly greater at Years 1, 2 and 3 when compared to baseline. CONCLUSIONS: Our findings suggest that despite physical decline, individuals with FRDA have relatively stable mental well-being. This study demonstrates that the SF-36V2 is unlikely to be a useful tool for identifying clinical change in FRDA therapeutic trials.

Binaural speech processing in individuals with auditory neuropathy.

Auditory neuropathy disrupts the neural representation of sound and may therefore impair processes contingent upon inter-aural integration. The aims of this study were to investigate binaural auditory processing in individuals with axonal (Friedreich ataxia) and demyelinating (Charcot-Marie-Tooth disease type 1A) auditory neuropathy and to evaluate the relationship between the degree of auditory deficit and overall clinical severity in patients with neuropathic disorders. Twenty-three subjects with genetically confirmed Friedreich ataxia and 12 subjects with Charcot-Marie-Tooth disease type 1A underwent psychophysical evaluation of basic auditory processing (intensity discrimination/temporal resolution) and binaural speech perception assessment using the Listening in Spatialized Noise test. Age, gender and hearing-level-matched controls were also tested. Speech perception in noise for individuals with auditory neuropathy was abnormal for each listening condition, but was particularly affected in circumstances where binaural processing might have improved perception through spatial segregation. Ability to use spatial cues was correlated with temporal resolution suggesting that the binaural-processing deficit was the result of disordered representation of timing cues in the left and right auditory nerves. Spatial processing was also related to overall disease severity (as measured by the Friedreich Ataxia Rating Scale and Charcot-Marie-Tooth Neuropathy Score) suggesting that the degree of neural dysfunction in the auditory system accurately reflects generalized neuropathic changes. Measures of binaural speech processing show promise for application in the neurology clinic. In individuals with auditory neuropathy due to both axonal and demyelinating mechanisms the assessment provides a measure of functional hearing ability, a biomarker capable of tracking the natural history of progressive disease and a potential means of evaluating the effectiveness of interventions.

A retrospective review of X-linked Charcot-Marie-Tooth disease in childhood.

OBJECTIVE: X-linked Charcot-Marie-Tooth disease (CMTX) is infrequently diagnosed in childhood, and its clinical and neurophysiologic features are not well-described. We reviewed clinical, neurophysiologic, and pathologic findings in 17 children with CMTX. METHODS: This was a retrospective review of children with CMTX from 2 tertiary pediatric hospitals. The diagnosis of CMTX was based on an identifiable connexin 32 mutation (CMTX1) or a consistent pedigree and neurophysiologic features in children without a connexin 32 mutation (CMTX-other). RESULTS: Six boys and 2 girls from 8 kindreds had CMTX1, and 8 boys and 1 girl from 5 kindreds had other forms of CMTX (CMTX-other). Fifteen children, including males and carrier females, were symptomatic from infancy or early childhood (younger than 5 years). In addition to the typical Charcot-Marie-Tooth disease clinical phenotype, some patients had delayed motor development, sensorineural hearing loss, tremor, pathologic fractures, or transient CNS disturbances. Eleven children underwent nerve conduction studies. Median nerve motor nerve conduction velocities were in the intermediate to normal range (30-54 m/s) in all children older than 2 years. Axon loss, reflected by low-amplitude compound muscle action potentials, was present in all patients. A pattern of X-linked dominant inheritance, with carrier females showing an abnormal neurologic or neurophysiologic examination, correlated with the presence of a connexin 32 mutation in all but 2 pedigrees. CONCLUSIONS: The clinical phenotype of CMTX is broader than previously reported. Onset in males and carrier females is most often in early childhood. Families with an X-linked dominant inheritance pattern are likely to have CMTX1.

Corrosion resistance of iron-platinum magnets.

OBJECTIVES: The objective of this study was to investigate the corrosion resistance of the prototype iron-platinum (FePt) magnets and non-encapsulated neodymium-iron-boron (NdFeB) magnets in three different pH environments. METHODS: The corrosion resistance of the magnets was studied using a corrosion indicator, the breakaway force. The breakaway forces of the magnets after immersion in three media, namely 1% lactic acid solution (pH=2.7), 0.1% sodium sulphide solution (pH=12) and adjusted artificial saliva (pH=6.8) were compared after 28 and 60-day periods. RESULTS: By day 7, all NdFeB magnets dissolved completely in the acid medium, and they showed significantly lower breakaway forces at day 28 and day 60 in artificial saliva (90%, 69%) and in alkaline medium (67%, 42%). In contrast, the FePt magnets did not show a drop in the breakaway forces after immersion in acid or artificial saliva, although approximately half of the original breakaway forces were recorded at day 28 and day 60 after immersion in strong alkali. CONCLUSIONS: The new iron-platinum magnets, which require no yoke assembly or protective casing, has good corrosion resistance for the oral environment. If its retentive force can be improved without increasing its thickness (0.3 mm), then it will have distinct advantages for clinical use.

Voice activity and participation profile: assessing the impact of voice disorders on daily activities.

Traditional clinical voice evaluation focuses primarily on the severity of voice impairment, with little emphasis on the impact of voice disorders on the individual's quality of life. This study reports the development of a 28-item assessment tool that evaluates the perception of voice problem, activity limitation, and participation restriction using the International Classification of Impairments, Disabilities and Handicaps-2 Beta-1 concept (World Health Organization, 1997). The questionnaire was administered to 40 subjects with dysphonia and 40 control subjects with normal voices. Results showed that the dysphonic group reported significantly more severe voice problems, limitation in daily voice activities, and restricted participation in these activities than the control group. The study also showed that the perception of a voice problem by the dysphonic subjects correlated positively with the perception of limitation in voice activities and restricted participation. However, the self-perceived voice problem had little correlation with the degree of voice-quality impairment measured acoustically and perceptually by speech pathologists. The data also showed that the aggregate scores of activity limitation and participation restriction were positively correlated, and the extent of activity limitation and participation restriction was similar in all except the job area. These findings highlight the importance of identifying and quantifying the impact of dysphonia on the individual's quality of life in the clinical management of voice disorders.

Phonological disruption and subsequent self-correcting behaviour in Cantonese aphasic speakers.

This study investigated the phonological disruption and subsequent self-correcting behaviour in Cantonese aphasic speakers. The self-correcting behaviour was investigated by examining the sequence of successive spontaneous attempts in producing a target sound. Five anomic, five non-fluent aphasic and five normal control subjects were assessed by using a confrontation naming task which included monosyllabic, disyllabic and trisyllabic targets. All the aphasic subjects demonstrated successive phonological self-corrections towards the target. Initial consonants were more vulnerable to phonological disruption and more resistant to self-correction than vowels, lexical tones and final consonants.

Speech intelligibility in tone language (Chinese) laryngectomy speakers.

Tone language speakers use lexical tone or fundamental frequency to signal meaning. Therefore, native tone language alaryngeal speakers encountering difficulty imparting lexical tone variation would suffer loss of speech intelligibility. This study examines the intelligibility of lexical tone produced by four different alaryngeal speech methods, namely: oesophageal speech, electrolarynx, a pneumatic device and tracheo-oesophageal speech. Isolated and embedded monosyllabic Chinese words produced by 53 alaryngeal speakers were presented to three normally hearing, young adult listeners with no prior exposure to laryngectomy speech. The listeners transcribed the speech orthographically. Significant differences were found in the intelligibility level between the different speech methods. Listeners' responses were also pooled together and analysed for tone and segmental errors. Errors of tone alone were found to occur more often than segmental errors.

Language screening in preschool Chinese children.

The incidence of language delay in Chinese preschool children was studied by a stratified proportional sampling of all 3 year olds in Hong Kong. The Developmental Language Screening Scale (DLSS) devised for use with Cantonese speaking children was used to identify children with language delay. Of 855 children sampled in the stage I screening procedure, 4%, 2.8% and 3.3% were identified as having delay in verbal comprehension, expression or both respectively. The stage II clinical diagnostic study included a randomly selected group of children screened in stage I with or without any associated behavioural problem. Among these, 3.4% were identified as having a language delay using the Reynell Language Developmental Scale (RDLS) with a criterion of language age of less than or equal to two-thirds of the chronological age; 3% had specific language delay using the criteria of language age less than or equal to two-thirds the chronological age and developmental age more than or equal to two-thirds the chronological age. More boys were found to have language delay, although this was not statistically significant.