Suitability of acoustic perturbation measures in analysing periodic and nearly periodic voice signals

In recent years, acoustic perturbation measurement has gained clinical and research popularity due to the ease of availability of commercial acoustic analysing software packages in the market. However, because the measurement itself depends critically on the accuracy of frequency tracking from the voice signal, researchers argue that perturbation measures are not suitable for analysing dysphonic voice samples, which are aperiodic in nature. This study compares the fundamental frequency, relative amplitude perturbation, shimmer percent and noise-to-harmonic ratio between a group of dysphonic and non-dysphonic subjects. One hundred and twelve dysphonic subjects ( 93 females and 19 males) and 41 non-dysphonic subjects ( 35 females and 6 males) participated in the study. All the 153 voice samples were categorized into type I ( periodic or nearly periodic), type II ( signals with subharmonic frequencies that approach the fundamental frequency) and type III ( aperiodic) signals. Only the type I ( periodic and nearly periodic) voice signals were acoustically analysed for perturbation measures. Results revealed that the dysphonic female group presented significantly lower fundamental frequency, significantly higher relative amplitude perturbation and shimmer percent values than the non-dysphonic female group. However, none of these three perturbation measures were able to differentiate between male dysphonic and male non-dysphonic subjects. The noise-to-harmonic ratio failed to differentiate between the dysphonic and non-dysphonic voices for both gender groups. These results question the sensitivity of acoustic perturbation measures in detecting dysphonia and suggest that contemporary acoustic perturbation measures are not suitable for analysing dysphonic voice signals, which are even nearly periodic. Copyright (C) 2005 S. Karger AG, Basel.

Articulatory imprecision in dysarthria following childhood cerebellar tumor: A perceptual and acoustic investigation of three male participants

Articulatory imprecision has been documented as a key perceptual feature of the dysarthria associated with childhood cerebellar tumor (CCT). As yet the underlying acoustic and physiological characteristics of motor speech production that contribute to this perceptual feature have not been identified. The aim of the current study was to describe perceptual and acoustic characteristics of consonant production in three children with dysarthria associated with CCT The results indicated that in all three cases the timing of articulatory movements during stop consonant production differed from that measured in a control group of same-age peers. The impact of cerebellar lesions in adulthood on articulatory gestures is used as a reference for discussing the findings of the current study with similarities evident. Also discussed are future research directions for examining the underlying acoustic or physiological basis for articulatory imprecision in children with dysarthria associated with CCT.

Long-term oral sensitivity and feeding skills of low-risk pre-term infants

This study examined the oral sensitivity and feeding skills of low-risk pre-term infants at 11-17 months corrected age. Twenty pre-term infants (PT) born between 32 and 37 weeks at birth without any medical comorbidities were assessed. All of this PT group received supplemental nasogastric (NG) tube feeds during their birth-stay in hospital. A matched control group of 10 healthy full-term infants (FT) was also assessed. Oral sensitivity and feeding skills were assessed during a typical mealtime using the Royal Children's Hospital Oral Sensitivity Checklist (OSC) and the Pre-Speech Assessment Scale (PSAS). Results demonstrated that, at 11-17 months corrected age, the PT group displayed significantly more behaviours suggestive of altered oral sensitivity and facial defensiveness, and a trend of more delayed feeding development than the FT group. Further, results demonstrated that, relative to the FT group, pre-term infants who received greater than 3 weeks of NG feeding (PT>3NG) displayed significantly more facial defensive behaviour, and displayed significant delays across more aspects of their feeding development than pre-term infants who received less than 2 weeks of NG feeding (PT

Postural and respiratory activation of the trunk muscles changes with mode and speed of locomotion

Despite the importance of the deep intrinsic spinal muscles for trunk control, few studies have investigated their activity during human locomotion or how this may change with speed and mode of locomotion. Furthermore, it has not been determined whether the postural and respiratory functions, of which these muscles take part, can be coordinated when locomotor demands are increased. EMG recordings of abdominal and paraspinal muscles were made in seven healthy subjects using fine-wire and surface electrodes. Measurements were also made of respiration and gait parameters. Recordings were made for 10s as subjects walked on a treadmill at 1 and 2 ms(-1) and ran at 2, 3, 4 and 5 ms(-1). Unlike the superficial muscles, transversus abdominis was active tonically throughout the gait cycle with all tasks, except running at speeds of 3 ms(-1) and greater. All other muscles were recruited in a phasic manner. The relative duration of these bursts of activity was influenced by speed and/or mode of locomotion. Activity of all abdominal muscles, except rectus abdominis (RA), was modulated both for respiration and locomotor-related functions but this activity was affected by the speed and mode of locomotion. This study provides evidence that the deep abdominal muscles are controlled independently of the other trunk muscles. Furthermore, the pattern of recruitment of the trunk muscles and their respiratory and postural coordination is dependent on the speed and mode of locomotion. (C) 2003 Published by Elsevier B.V.

Evaluating the role of speech-language pathology with patients with communication disability in the acute hospital setting using the ICF

The practice of speech-language pathology in the acute care hospital setting has changed dramatically over the last 20 years. Speech-language pathologists now routinely assess and manage patients with dysphagia as well as patients with acquired communication disorders. In practice, clinicians have tended to direct their limited resources toward the assessment and management of patients with dysphagia before addressing the needs of patients with acquired communication disorders. This practice has resulted in a decline in speech-language pathology services for patients with communication disorders and has led some clinicians to question the role of the speech-language pathologist in the acute care hospital setting. This article continues this discussion by evaluating the role of the speech-language pathologist in the acute care hospital setting within the context of the World Health Organization's (WHO) International Classification of Functioning, Disability and Health (ICF; WHO, 2001). It argues that by adopting the ICF, speech-language pathologists have a sound rationale for broadening their role to identify the communication needs of all hospital inpatients who experience communication difficulties in the acute care hospital setting.

Foot orthotics in the treatment of lower limb conditions: A musculoskeletal physiotherapy perspective

Orthotic therapy is frequently advocated for the treatment Of musculoskeletal pain and injury of the lower limb. The clinical efficacy, mechanical effects, and Underlying mechanism of the action of foot orthotics has not been Conclusively determined making it difficult for practitioners to agree on a reliable and valid clinical approach to their application and indeed even their fabrication. This problem is compounded by evidence suggesting that the most commonly used approach for orthotic prescription, the (Biomechanical Evaluation of the Foot. Vol. 1. Clinical Biomechanics Corporation, Los Angeles, 1971) approach, has poor validity and many of the associated clinical measurements of that approach lack adequate levels of reliability. This paper proposes a new approach that is based on two key elements. One is the identification, verification and quantification of physical tasks that serve as client specific outcome measures. The second is the application of specific physical manipulations during the performance of these physical tasks. The physical manipulations are selected on the basis of motion dysfunction and their immediate effects on the client specific outcome measures serve as the basis to making an informed decision on the propriety of using orthotics in individual clients. The motion dysfunction also guides the type of orthotic that is applied. Practical case examples as well Lis generic and specific guidelines to the application of this clinical assessment process and orthotics are provided in this paper. (C) 2004 Published by Elsevier Ltd.

Rehabilitation after total knee replacement via low-bandwidth telemedicine: the patient and therapist experience

After a total knee replacement, inadequate rehabilitation is associated with poor physical outcomes and a reduced longevity of the knee prosthesis. We have developed a low-bandwidth telemedicine system to enable rehabilitation services to be delivered directly to the home of patients in rural and remote areas. We have examined the experience of clinical physiotherapists and of 31 participants who received treatment via the system. High levels of satisfaction were reported by participants (mean responses >7 on a 10 cm visual analogue scale). The service was found to be effective, safe and easy to use, and it integrated well into current clinical practice. The study demonstrates the potential for delivering physiotherapy services via low-bandwidth Internet connections.

Verb and context processing in Parkinson's disease

The aim of the present study was to investigate verb and context processing in 10 individuals with Parkinson's disease (PD) and matched controls. A self-paced stop making sense judgment task was employed where participants read a sentence preceded by a context which made the thematic role of the verb plausible or implausible. Participants were required to indicate whether the sentence ceased to make sense at any point by responding yes/no at each word. PD participants were less accurate than the control participants at detecting sentence anomalies based on verb selection restrictions and previously encountered contextual elements. However, further research is required to determine the precise nature of the grammatical processing disturbance associated with PD. (c) 2005 Elsevier Ltd. All rights reserved.