Guy G. Simoneau

Postural Instability in Patients with Diabetic Sensory Neuropathy

OBJECTIVE Recent survey evidence suggests that sensory ataxia due to diabetic neuropathy may be a more frequent and serious problem than is commonly recognized. This view is further supported by research that confirms the major contribution of the somatosensory system to the control of posture. We therefore sought to determine the effects of significant diabetic distal symmetrical polyneuropathy on the control of posture. RESEARCH DESIGN AND METHODS Fifty-one subjects, divided into three groups, participated in this study. Seventeen had diabetes and significant sensory neuropathy, 17 had diabetes and no neuropathy, and 17 had neither diabetes nor neuropathy. The subjects were matched across groups, and stringent exclusion criteria were applied. Postural stability during quiet standing was measured using a force platform. In addition to electrophysiological and quantitative sensory tests of neuropathy, a number of physical and functional characteristics were measured for all subjects. RESULTS Postural instability was found to be significantly associated with sensory neuropathy, but not with diabetes per se. Patients with sensory neuropathy demonstrated between 66 and 117% more instability than did control subjects (depending on the testing condition). Based on multiple linear regression analyses, the most significant correlates of instability were the quantitative sensory measures of neuropathy and age. CONCLUSIONS The loss of sensory perception secondary to diabetic distal symmetrical sensory neuropathy has a markedly detrimental effect on postural stability. The deficit is greatest when visual or vestibular cues are absent or degraded. Patients with neuropathy need to be informed of the postural consequences of this condition to limit the potential morbidity caused by falls.

Role of somatosensory input in the control of human posture

Abstract In this study we investigated the effects of somatosensory deficits on the control of balance during quiet stance using subjects with demonstrated loss of sensation to touch, joint movement perception, proprioception, and other somatosensory stimuli secondary to diabetic neuropathy. The results indicate that somatosensory deficits resulting from diabetic neuropathy lead to a marked decrease in the ability to maintain a stable stance position. Furthermore, this study clearly demonstrates that somatosensory function is at least as important as vision in the control of posture during quiet stance, and that the visual and vestibular systems cannot fully compensate for diminished somatosensory input.

Diabetic sensory neuropathy effect on ankle joint movement perception

OBJECTIVE To determine if diabetic subjects with lower extremity cutaneous sensory neuropathy also have a loss of ankle joint movement perception. The strength of association between measurements of ankle joint movement perception and measures of cutaneous sensory function was also investigated. DESIGN Diabetic subjects with and without sensory neuropathy and individuals without diabetes participated in this study. SETTING All subjects were community-living individuals. PARTICIPANTS Fifty-one subjects, ages 40 to 68. Seventeen of the 34 subjects with diabetes had significant distal sensory neuropathy as determined by cutaneous perception of mechanical vibration. All individuals without diabetes were volunteers from the community. Most subjects with diabetes were recruited through direct referral from their physicians. INTERVENTIONS Ankle joint movement perception threshold (JMPT) was assessed using a device designed for this study. Cutaneous sensory function under both halluces was measured for vibration perception using a vibrometer and for touch-pressure perception using Semmes-Weinstein monofilaments. MAIN OUTCOME MEASURES Ankle JMPTs (degrees) were compared to measurements of cutaneous vibration perception (volts) and touch-pressure perception (monofilaments force ratings). RESULTS Diabetic subjects with cutaneous sensory neuropathy demonstrated a significant loss of ankle movement perception (p < .01). Correlation between JMPT and cutaneous sensory tests ranged from Spearmans rank r = .43 to .67. CONCLUSIONS Although individuals with cutaneous sensory loss secondary to diabetic neuropathy also demonstrated loss of movement perception at the ankle, the relatively low explained variance between the two types of assessment (18% to 45%) indicates that the severity of ankle joint movement perception deficits cannot be directly implied from cutaneous sensory tests.

Walker-assisted gait in rehabilitation: a study of biomechanics and instrumentation

While walkers are commonly prescribed to improve patient stability and ambulatory ability, quantitative study of the biomechanical and functional requirements for effective walker use is limited. To date no one has addressed the changes in upper extremity kinetics that occur with the use of a standard walker, which was the objective of this study. A strain gauge-based walker instrumentation system was developed for the six degree-of-freedom measurement of resultant subject hand loads. The walker dynamometer was integrated with an upper extremity biomechanical model. Preliminary system data were collected for seven healthy, right-handed young adults following informed consent. Bilateral upper extremity kinematic data were acquired with a six camera Vicon motion analysis system using a Micro-VAX workstation. Internal joint moments at the wrist, elbow, and shoulder were determined in the three clinical planes using the inverse dynamics method. The walker dynamometer system allowed characterization of upper extremity loading demands. Significantly differing upper extremity loading patterns were Identified for three walker usage methods. Complete description of upper extremity kinetics and kinematics during walker-assisted gait may provide insight into walker design parameters and rehabilitative strategies.

Wrist and Forearm Posture From Typing on Split and Vertically Inclined Computer Keyboards

A study was conducted on 90 experienced office workers to determine how commercially available alternative computer keyboards affected wrist and forearm posture. The alternative keyboards tested had the QWERTY layout of keys and were of three designs: split fixed angle, split adjustable angle, and vertically inclined (tilted or tented). When set up correctly, commercially available split keyboards reduced mean ulnar deviation of the right and left wrists from 12° to within 5° of a neutral position compared with a conventional keyboard. The finding that split keyboards place the wrist closer to a neutral posture in the radial/ulnar plane substantially reduces one occupational risk factor of workrelated musculoskeletal disorders (WMSDs): ulnar deviation of the wrist. Applications of this research include commercially available computer keyboard designs that typists can use and ergonomists can recommend to their clients in order to minimize wrist ulnar deviation from typing.

Wrist and forearm postures of users of conventional computer keyboards

The aim of this study was to perform a comprehensive investigation to document wrist and forearm postures of users of conventional computer keyboards. We instrumented 90 healthy, experienced clerical workers with electromechanical goniometers to measure wrist and forearm position and range of motion for both upper extremities while typing. For an alphabetic typing task, the left wrist showed significantly greater (p < .01) mean ulnar deviation (15.0° ± 7.7°) and extension (21.2° ± 8.8°) than the right wrist (10.1° ± 7.2° and 17.0° ± 7.4° for ulnar deviation and extension, respectively). Conversely, the right forearm had greater mean pronation (65.6° ± 8.3°) than the left forearm (62.2° ± 10.6°). We noted minimal functional differences in the postures of the wrists and forearms between alphabetic and alphanumeric typing tasks. Ergonomists should consider the statistically significant and probable practical difference in wrist and forearm posture between the left and right hand in ergonomic interventions in the office and in the design of computer keyboards. Actual or potential applications of this research include guiding the design of new computer keyboards.

Clinical Trial Registration in Physical Therapy Journals: Recommendations from the International Society of Physiotherapy Journal Editors

Clinical trial registration involves placing the protocol for a clinical trial on a free, publicly available, and electronically searchable register. Registration is considered to be prospective if the protocol is registered before the trial commences (ie, before the first participant is enrolled). Prospective registration has several potential advantages. It could help avoid trials being duplicated unnecessarily, and it could allow people with health problems to identify trials in which they might participate. Perhaps more important, however, it tackles 2 big problems in clinical research: selective reporting and publication bias. Selective reporting involves investigators reporting only the most favorable results when they publish a trial, instead of reporting the results for all the outcomes that were measured. Reporting only favorable outcomes can create a misleading appearance of the effect of a therapy in the published literature. For example, imagine that a completely ineffective intervention is tested across several trials, and each trial measures multiple outcomes. Most outcomes will show no significant effect of the intervention. However, occasionally an outcome will show significant benefit or harm simply by chance. If the researchers publish the positive outcomes but not all of the nonsignificant and negative outcomes, readers could interpret falsely that the intervention is beneficial. A similar problem could occur when outcomes are analyzed at multiple time points. Researchers may report that an intervention improves walking speed at 6 months, but fail to mention that it does not improve walking speed at 1, 2, 3, 9, 12, and 24 months. Prospective registration of clinical trials combats this problem in several ways. Journal editors and reviewers can compare the range of outcomes reported in a manuscript against those listed in the registered protocol, requesting that any discrepancies be resolved by following the protocol. Readers also can compare the outcomes in the registered protocol against …

Effect of keyswitch design of desktop and notebook keyboards related to key stiffness and typing force

This study aimed to compare and analyse rubber-dome desktop, spring-column desktop and notebook keyboards in terms of key stiffness and fingertip typing force. The spring-column keyboard resulted in the highest mean peak contact force (0.86N), followed by the rubber dome desktop (0.68N) and the notebook (0.59N). All these differences were statistically significant. Likewise, the spring-column keyboard registered the highest fingertip typing force and the notebook keyboard the lowest. A comparison of forces showed the notebook (rubber dome) keyboard had the highest fingertip-to-peak contact force ratio (overstrike force), and the spring-column generated the least excess force (as a ratio of peak contact force). The results of this study could aid in optimizing computer key design that could possibly reduce subject discomfort and fatigue.

Influence of knee flexion angle and age on triceps surae muscle fatigue during heel raises.

Abstract Hébert-Losier, K, Schneiders, AG, García, JA, Sullivan, SJ, and Simoneau, GG. Influence of knee flexion angle and age on triceps surae muscle fatigue during heel raises. J Strength Cond Res 26(11): 3134–3147, 2012—The triceps surae (TS) muscle-tendon unit is 1 of the most commonly injured in elite and recreational athletes, with a high prevalence in middle-aged adults. The performance of maximal numbers of unilateral heel raises is used to assess, train, and rehabilitate TS endurance and conventionally prescribed in 0° knee flexion (KF) for the gastrocnemius and 45° for the soleus (SOL). However, the extent of muscle selectivity conferred through the change in the knee angle is lacking for heel raises performed to volitional fatigue. This study investigated the influence of knee angle on TS muscle fatigue during heel raises and determined whether fatigue differed between middle-aged and younger-aged adults. Forty-eight healthy individuals aged 18–25 and 35–45 years performed maximal numbers of unilateral heel raises in 0° and 45° KF. Median frequencies and linear regression slopes were calculated from the SOL, gastrocnemius medialis (GM), and gastrocnemius lateralis (GL) surface electromyographic signals. Stepwise mixed-effect regressions were used for analysis. The subjects completed an average of 45 and 48 heel raises in 0° and 45° KF, respectively. The results indicated that the 3 muscles fatigued during testing as all median frequencies decreased, and regression slopes were negative. Consistent with muscle physiology and fiber typing, fatigue was greater in the GM and GL than in the SOL (p < 0.001). However, knee angle did not influence TS muscle fatigue parameters (p = 0.814), with similar SOL, GM, and GL fatigue in 0° and 45° KF. These findings are in contrast with the traditionally described clinical use of heel raises in select knee angles for the gastrocnemius and the SOL. Furthermore, no difference in TS fatigue between the 2 age groups was able to be determined, despite the reported higher prevalence of injury in middle-aged individuals.

JOSPT: Plus Ultra—Further Beyond

JOSPT enters its 36th year of publishing guided by a new 3-year strategic plan, its third since 2008. This plan, created last September with the generous participation of JOSPTs many stakeholders, could be said to have as its motto “plus ultra,” Latin for “further beyond.” JOSPTs vision is to go further beyond where it is today to become the pre-eminent source of scientific evidence to optimize movement and health for the global community. Its mission, grounded in the past but driving toward the future, is to disseminate scientifically rigorous, clinically relevant content for physical therapists and others in the health care community to advance musculoskeletal and sports-related rehabilitation and movement. J Orthop Sports Phys Ther 2015;45(1):1–3. doi:10.2519/jospt.2015.0101