The effects of postural threat and the potential consequences of obstacle contact on the obstacle contact on the obstacle negotiation kinematics among younger and older adults were examined. Seventeen older (OA;7males, 10 females; mean age, 68.94 + 4.85) and fifteen younger adults (YA; 5males, 10 females; mean age, 22.53 + 2.77) negotiated virtual and real obstacles while walking at a self-determined velocity along a 7.2m walkway under 4 different conditions of postural threat. Postural threat was manipulated by varying the width (0.60m)) of the walkway. Postural threat altered crossing kinematics for all subjects. Specifically, age-related differences emerged with increasing postural threat, however the changes observed among older adults were considerably different from those of younger adults. Additionally, there was no effect for the potential consequences of obstacle contact, however, no age-related differences emerged. These results revealed an effect for postural threat and obstacle characteristics on the negotiation strategies of younger and older adults. Both postural threat and obstacle characteristics elicit conservative crossing kinematics in younger and older adults. Specifically, these findings illustrate age-dependent differences in obstacle negotiation strategies and that postural threat affects older adults differently than younger adults whereas the potential consequences of obstacle contact affects younger and older adults equally. / xii, 79 leaves ; 28 cm.

The effects of postural threat on postural control among younger and older adults were examined. Fifteen younger (YA;8 females and 7 males; mean age 22.00 + 2.17 years) and fifteen older (OA; 10 females and 5 males; mean age 69.98 + 5.35 years) adults performed quiet standing and forward reaching under four conditions of postural threat. Postural threat was achieved by the manipulation of height (low(0.43m) and high (1.4m)) and stepping constraint (unconstrained (0.91m from the anterior edge of an elevating platform) or constrained (0m from the anterior edge of an elevating platform). Younger and older adults demonstrated conservative modifications to postural control that may reduce the likelihood of a fall in tenuous conditions. Interestingly, age-related differences emerged in the mechanism of achieving these accomodations to postural threat. Our findings indicate that older adults may adopt more proximal postural strategies under condtion of postural threat. The shift toward a more proximal postural strategies under conditions of postural threat. The shift toward a more proximal control of balance may reflect the age-related declines in the ability to control the movement of the trunk. Although these adaptations appear benefical to older adults, the possibility exists for detrimental consequences to postural recovery following a balance disturbance. / xi, 173 leaves : ill. ; 29 cm.

Purpose: An open mouth approach is used in voice therapy for enhancing speech and voice production and relaxing the laryngeal musculature. The acoustic and physiological consequences of an open jaw posture, however, have not been clearly understood due to a paucity of cross-system studies taking the age effect into consideration. The major aims of this study are twofold (1) to examine if the geriatric voice may be improved using an “open jaw” posture and (2) if an aging effect on the voice of normal healthy adults can be detected through acoustic and physiological measures Method: The main part of this study involved simultaneous multi-channel voice recordings obtained from 85 healthy adults aged between 38 and 93 years. A convenience sampling strategy was used to recruit at least five females and five males in each of four age groups, 35-59 years (35+), 60-69 (60+), 70-79 (70+), and above 80 (80+). For simultaneous acoustic, electroglottographic (EGG), and jaw displacement recordings, participants were asked to perform two tasks which included a sustained vowel task and a sentence production task. The sustained vowel task involved sustaining the vowel /a/ in five different conditions, an isolated vowel /a/ produced at normal, low, and high pitch levels and the vowel /a/ initiated with a consonant (/m/ and /h/). The sentence production task involved production of the sentence 'We saw two cars,' containing the vowels /i, ɔ, u, a/. For simultaneous airflow-EGG recordings, participants were asked to sustain the vowel /a/ at normal pitch. For simultaneous airflow-air pressure-EGG recordings, participants were asked to repeat /pa/ five times in one breath. Participants were asked to perform all of the tasks using two jaw postures (normal and open). A series of univariate analysis of variances were used to identify instrumental measures sensitive for discriminating between the four age groups and the two jaw postures. A follow-up perceptual study was conducted to determine the effect of an open jaw posture on vowel intelligibility and voice clarity. A quota sampling strategy was used to recruit 40 normal hearing participants, including 20 females (age range = 18-42 years, mean = 25.3, SD = 7.9) and 20 males (age range = 18-47, mean = 23.6, SD = 6.7). These listeners were presented with vowels segmented from the sentences recorded in the first experiment and asked to perform a vowel identification and a voice clarity discrimination task. The vowel samples were taken from 40 speakers, with five females and five males in each of the four age groups (35+, 60+, 70+, and 80+). The percentages of correct vowel identification for voices produced with normal and open jaw postures were compared. The percentages of vowels judged as 'clearer' in a normal-open jaw contrast pairs were also calculated for comparison. Results: Significant age group effects were found in this study for both genders on fundamental frequency (F0), voice onset time (VOT) (/ka/), open quotient (OQ), and speed quotient (SQ), with additional age differences detected for females on %jitter, %shimmer, signal-to-noise ratio (SNR), and the second formant frequency (F2), and for males a significant age group effect was found on VOT (/tu/). Results for both females and males revealed significant open jaw posture effects on F0, F2, VOT (/ka/), MFR, SPL and vowel space area. In addition, for females significant posture effects were found on F1, subglottal pressure and the H1-H2 amplitude difference, and for males, significant posture effects were found on %jitter and VOT-/tu/. Results from the follow-up perceptual study revealed that an open jaw posture was associated with better vowel identification and better voice clarity. Conclusions: A selection of instrumental measures was shown to be useful for detecting voice changes due to aging. Instrumental and perceptual evidence was found that an open jaw posture was associated with positive changes in vocal behaviours, including improved phonatory stability, vocal power, and voice clarity.

No description available.

With the aging population on the rise, the prevalence of heart failure is expected to increase in the coming years. Heart failure is independently correlated with cognitive decline and has a negative impact on quality of life, morbidity and mortality. Reduced cardiac output (Q) and cerebral blood flow (CBF) are proposed mechanistic links between heart failure and cognitive decline; however, reports are limited to the supine position and the response to an everyday upright posture is unknown. The purpose of this thesis was to primarily investigate the CBF response to a common upright seated position encountered in daily life in heart failure patients compared to healthy age- and sex-matched controls. Furthermore, we sought to determine whether cognitive performance or cognitive-activated hemodynamics were posture-dependent in the heart failure group. The secondary objective of this thesis was to be inclusive to patients that represent those encountered in clinical practice???specifically to include patients with higher left ventricular ejection fractions (LVEF) and atrial fibrillation with co-existing heart failure. Our findings confirmed greater cognitive impairments and a low supine CBF and Q in heart failure compared to controls and importantly, for the first time, a greater reduction in CBF with an upright seated position compared to healthy age- and sex- matched controls. When a cognitive task was performed supine and seated, performance outcomes were independent of posture in heart failure patients. However, mean flow velocity through the middle cerebral artery (MFV_MCA) increased less in response to the cognitive task seated. With regard to our secondary objectives, the results suggest that those with higher LVEF are equally at risk for cognitive decline and cerebral hypoperfusion due to a low Q. Furthermore, high variability in Q and MFV_MCA were detected in association with the beat-to-beat variation inherent to atrial fibrillation and suggest that this may be an underappreciated pathway to cognitive impairments in this sub-group. Together, these results suggest that upright cerebral hypoperfusion throughout the day may contribute to cognitive decline in heart failure and create a basis for further work to be done with larger sample sizes. Moreover, cerebral hypoperfusion with higher LVEF and the blood flow variation in atrial fibrillation represent important pathways contributing to cognitive decline in these under investigated sub-groups.

It is well establish that posture deformities are a common problem among children that is often ignored by parent and teachers. Posture deformities in children could be related to their socio-economic status, lifestyle, culture, tradition, environmental factors, as well as activity levels and are associated with numerous adverse health effects, which include lung and heart defects, indigestion and back pain. Children who experience back pain are at increased risk of having back pain as adults. The economic impact of back pain affects the industry, were back problems are the most expensive type of injury claim. The increase in spinal problems, such as lower back pain in children and adolescents, points to the need for continued screening. It is suggested that early detection of postural deviation could provide an improve chance for corrective remedies and posture development. On investigating the relevant literature it becomes clear that attempts to define the prevalence of posture deformities among children have focused on reporting selected deformities only. Consequently the literature contains insufficient information on posture deformities involving the entire musculoskeletal system, as well as the prevalence of posture deformities among black African people. The purpose of this study was firstly to determine the incidence of posture deviations among black African children in the North West Province and secondly to determine the difference in the prevalence of posture deformities between boys and girls. In a longitudinal study posture deformities including the entire musculoskeletal system were assessed in 251 schoolchildren (136 girls and 115 boys). Posture screening was done according to the New York Posture test and a posture grid. Subjects were evaluated in a standing position from the rear and lateral side. Foot deformities (flat foot) were also measured with the use of white chalk and a black board. Thereafter the "Adam's test" (forward bending test) were used for further scoliosis evaluation. The prevalence of posture deformities was reported to be high among black African schoolchildren. The incidence of lordosis (84%) and protruding abdomen (67%) was the highest, while twisted head (8%) was reported as the lowest. Gender difference in the prevalence of posture deformities was also found, with a higher incidence of posture deformities reported in girls (54%) as in boys (46%). / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.

The aim of this study was to determine the combined effects of high-heeled shoes and load carriage on gait and posture adaptation. Furthermore, the adaptation of gait and posture to the combined two conditions was examined by a comparison of the measured parameters between experienced and novice groups. 30 participants underwent a quantitative measurement of temporospatial, kinematic, and kinetic parameters of hip, knee, and ankle on both loaded and unloaded limbs using 3D motion analysis. Double support time and stride length increased during high-heeled gait and the magnitude of alteration was greater with a load. Increased plantarflexion was main cause of raised heel. Ankle plantarflexor moment increased with high-heeled but decreased with load carriage. As a result, plantarflexor moment diminished, in addition knee extensor moment exaggerated further. Hip extensor moment increased with heel height but not with load weight, however, hip angle was affected only by the load.

This thesis examined Autonomic Nervous System activity evoked by postural instability. Autonomic reactions were assessed using measures of electrodermal activity at the surface of the skin. Perturbation-evoked electrodermal responses (EDRs) were consistently observed in conjunction with both upper and lower limb postural reactions. These autonomic responses were sensitive to perturbation amplitude, as well as experimental manipulations which did not influence the perturbation itself but which affected response execution. In particular, stimulus predictability and movement challenge modulated EDRs, although purely cognitive manipulations did not significantly affect autonomic responses. Probes examining the potential role of such autonomic potentials in compensatory balance control revealed that EDRs evoked during compensatory postural reactions were larger and more consistent than potentials evoked by purely motor or sensory stimuli, suggesting that evoked autonomic activity plays a role in compensatory behavior. While the specific role of autonomic contributions in compensatory balance control require further study, speculative models for autonomic contributions propose either feedback-based pathways for detection of instability to initiate the postural reaction, and/ or an adaptive role to higher centers important for establishing sensorimotor gain in future conditions. This thesis presents new evidence regarding basic neural mechanisms engaged in the recognition and response to postural instability, and future work may extend these findings in clinical populations with high fall incidence and offer clues as to alternative causes for falls and fall prevention.

Thesis (M App Sci in Physiotherapy) --University of South Australia, 1992

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.