Joint pain, physical function, and balance self-confidence in acromegaly versus nonfunctioning pituitary adenoma patients.

CONTEXT: Patients with acromegaly (PWA) experience balance issues, despite achieving biochemical remission, that may significantly impair their quality of life. OBJECTIVE: We sought to assess the prevalence of falls and balance self-confidence in PWA in comparison with a control group. Furthermore, we investigated the effect of joint pain and function as predictors for their balance self-confidence. DESIGN: Cross-sectional, case-controlled. SETTING: Tertiary care centers. PARTICIPANTS: In this case-control study, we surveyed PWA (n = 94) and nonfunctioning pituitary adenoma (PNA; n = 82) with similar age, sex, and body mass index from two Canadian centers. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Data were obtained on number of falls during the past 12 months, self-confidence to maintain balance, joint pain, joint surgery, pain medication usage, and upper and lower extremity musculoskeletal disability. RESULTS: While both PWA and PNA had a similarly high risk of falls, PWA had lower self-confidence to maintain balance (P < .01). Patients with acromegaly had higher joint pain scores and more functional impairment in upper extremity, hip, knee, and ankle joints (all P < .01). In both groups, age, sex, and ankle functional score were predictors of balance self-confidence. For PWA, hip functional score was also a predictor of balance self-confidence in contrast to knee and back pain scores being predictors for the PNA group. CONCLUSIONS: We confirmed an increased prevalence of falls in both groups with diminished balance confidence in PWA. This reduced balance self-confidence seems to be related to their increased hip functional impairment in comparison with PNA.

Effect of travel direction and wheelchair position on the ease of a caregiver getting an occupied wheelchair across a soft surface: a randomized crossover trial.

PURPOSE: To test the hypotheses that, in comparison with pushing an occupied upright manual wheelchair forward, pulling backward on the push-handles improves the objective and subjective ease with which a caregiver can get the wheelchair across a soft surface (e.g., grass, mud, sand, gravel); and the ease with which a caregiver can get the wheelchair across a soft surface improves if the wheelchair is tipped back into the wheelie position. METHODS: We used a randomized crossover trial with within-participant comparisons to study 32 able-bodied pairs of simulated caregivers and wheelchair occupants. The caregiving participants moved an occupied manual wheelchair 5 m across a soft surface (7.5-cm-thick gym mats) under four conditions (upright-forward, upright-backward, wheelie-forward and wheelie-backward) in random order. The main outcome measure was time (to the nearest 0.1 s) and the main secondary measure was the ease of performance (5-point Likert scale). RESULTS: The upright-backward condition was the fastest (p < 0.05) and had the highest ease-of-performance scores. In the forward direction, there was no statistically significant difference in the time required between the upright and wheelie positions, but the wheelie position was considered easier. CONCLUSIONS: Although further study is needed, our findings suggest that caregivers should pull rather than push occupied wheelchairs across soft surfaces. In the forward direction, caregivers may find the wheelie position easier than the upright condition. These techniques have the potential to both improve the effectiveness of and reduce injuries to caregivers. Clinical Trial Registration Number: NCT 04998539Implications for RehabilitationCaregivers should pull rather than push occupied manual wheelchairs across soft surfaces.In the forward direction, caregivers may find the wheelie position easier than and preferable to the upright condition.These techniques have the potential to both improve the effectiveness of and reduce injuries to caregivers.

Using principal component analysis to investigate pacing strategies in elite international canoe kayak sprint races.

The aim of this research was to use principal component analysis (PCA) to investigate the current pacing strategies of elite canoe kayak sprint athletes and to determine if there are differences in pacing patterns between medallists and non-medallists at major international competitions. Velocity data collected using global positioning systems (GPS) from all a-finals of major international competitions in 2016-2017 (including canoe and kayak, single and crew boat, and male and female) were downloaded from the International Canoe Federation's website. Data were normalised by the average velocity within each race and organised by race distance. In total 10, 14 and 16 races were analysed, and they followed all-out, positive, and 'seahorse-shaped' pacing strategies for the 200 m, 500 m, and 1000 m events, respectively. Normalised velocity PC1 (p = 0.039, ES = -0.44) and PC2 scores (p < 0.001, ES = -0.73) for 1000 m races were significantly different between medallists and non-medallists; however, significant differences between PCs were not found between groups in shorter race distances (i.e. 200 m and 500 m). Data collected using GPS provide information that can be used to better prepare athletes for canoe kayak sprint races lasting between 30 s and 240 s in duration.

The validation of a low-cost inertial measurement unit system to quantify simple and complex upper-limb joint angles.

The purpose of this research was to validate the use of a low-cost IMU system to measure upper-limb joint angles by comparing it to passive optical motion capture measures. Fifteen participants (five females; 25.9 ± 4.7 years) completed one trial of four simple range of motion (ROM) movements (elbow flexion/extension, shoulder abduction/adduction, shoulder flexion/extension, and shoulder internal/external rotation), and three complex functional daily tasks [hand to: back pocket (HBP), contralateral shoulder (HCS), head (HTH)]. Movements were measured, simultaneously, using fourteen OptiTrack cameras and five Notch® IMUs. The mean joint angle difference between devices ranged from 0.10° ± 3.11° for the HBP shoulder internal/external movement to 44.95° ± 3.50° for the simple ROM shoulder internal/external rotation movement. Nine of sixteen movement and plane comparisons showed significant differences between the device-specific movement cycle waveforms. Eleven of the comparisons showed either fixed and/or proportional biases (fixed only: 9; proportional only: 1; both fixed and proportional: 1). Due to multiple movements having large amplitude errors, low waveform similarities, and/or statistically significant mean differences between the Notch® IMUs and the gold-standard motion capture devices, we cannot recommend that Notch® IMUs are valid devices for measuring upper-limb joint angles during simple ROM and complex functional daily tasks.

Pacing strategies and relationships between speed and stroke parameters for elite sprint kayakers in single boats.

The study aimed to determine the pacing strategies of elite single-boat sprint kayakers, as well as the relationships between stroke parameters (stroke rate (SR) and stroke length (SL)) and kayak speed throughout the race. High-resolution split speed and stroke parameter data from men's (MK1) and women's (WK1) single-boat A- and B-finals in 2016-2017 international sprint kayak competitions were analysed. Correlation coefficients were calculated between SR-speed and SL-speed during each split for each race group. Athletes followed all-out, positive and seahorse-shaped pacing strategies for the 200 m, 500 m and 1000 m races, respectively. SL-speed had greater correlations during the first half of the MK1 200 m race, whereas SR-speed had greater correlations during the second half. SR-speed correlations were greater than SL-speed correlations throughout the final 150 m of WK1 200 m races. There were large and very large correlations between SR-speed at the end of both the WK1 500 m and MK1 1000 m race distances, respectively, despite following different pacing strategies. Single-boat pacing strategies change due to race distance during major international sprint kayak competitions, whereas the relationships between stroke parameters and speed change depending on athlete sex and the race distance.

Using the Portapres® for the measurement of toe arterial blood pressure during movement: is it valid and reliable?

The aim of the study was to assess the validity and reliability of using the Portapres® to measure toe blood pressure during rest and exercise. Construct validity, concurrent validity, and interday reliability were assessed by measuring toe (Portapres®)) and brachial blood pressure in 16 nondisabled participants on consecutive days. Construct validity was assessed by pedaling on a cycle ergometer (6 revolutions per minute) and comparing the measured toe blood pressure to an estimated value based on orthostatic factors. Concurrent validity was assessed by comparing toe and brachial blood pressure during supine rest and following 10 min of cycling exercise. Interday reliability was assessed by recording toe and brachial blood pressure during supine rest on a second day. Construct validity analysis shows that the toe blood pressure signal was moderately correlated with the changes in heart-toe distance and that changes in toe blood pressure during slow cycling were similar to the estimated value. Resting toe and brachial mean arterial blood pressure showed concurrent validity with only a fixed bias explained by the change in orthostatic pressure and the toe-brachial index. Furthermore, cycling exercise was associated with an increase in brachial and a decrease in toe mean blood pressure. The interday reliability analysis showed no proportional or fixed bias for mean arterial blood pressure. Our study showed the feasibility of using the Portapres® to measure toe blood pressure during movement and can be used to study the effect of movement-related forces during cycling on toe blood pressure.

Electrochemical red-ox therapy of prostate cancer in nude mice.

Minimally invasive therapies are increasingly in demand for organ-confined prostate tumors. Electrochemical therapy (EChT) is attractive, as it relies on locally-induced reduction-oxidation reactions to kill tumor cells. Its efficacy for prostate cancer was assessed in human PC-3 and LNCaP tumor xenografts growing subcutaneously in nude mice (n = 80) by applying 2 Stainless Steel vs. 4 Platinum-Iridium (Pt-Ir) electrodes to deliver current densities of 10 to 35 mA/cm(2) for 30 or 60 min. The procedure was uneventful in 90% of mice. No difference in tumor vs. body temperature was observed. Changes at electrode-tumor junctions were immediate, with dryness and acidity (pH2-3) at the anode and oedema and alkalinity (pH10-12) at the cathode. This was accompanied by cellular alterations, found more pronounced at the cathode. Such acidic and alkaline conditions were cytotoxic in vitro and dissolved cells at pH>10. In mice, tumor destruction was extensive by 24h with almost undetectable blood prostate specific antigen (LNCaP model) and covered the whole tumor surface by 4 days. EChT was most efficient at 25-30 mA/cm(2) for 60 min, yielding the longest recurrence-free survival and higher cure rates, especially with 4 Pt-Ir electrodes. EChT is a promising option to optimize for organ-confined prostate tumors.

Kinematic adaptations of spinal cord-injured subjects during obstructed walking.

STUDY DESIGN: A case-control study of walking over obstacles. OBJECTIVE: To characterize and compare the kinematic, anticipatory locomotor adjustments used by people with incomplete spinal cord injuries (SCIs). METHODS: The angular and linear kinematics of the lower limb when going over obstacles of low height (0.005 and 0.030 m) were compared between SCI subjects (n = 6) and able-bodied participants (n = 5). RESULTS: The results of this study show that even though SCI participants could adapt their kinematic patterns to go over obstacles, none of the participants used kinematic strategies similar to those of able-bodied participants. CONCLUSIONS: This difference could be explained in part by the absence in the SCI participants of increased hip flexion when going over the obstacles. Other confounding factors are discussed.

Increase in tibialis anterior motor cortex excitability following repetitive electrical stimulation of the common peroneal nerve.

The purpose of this study was to investigate whether repetitive electrical stimulation of the common peroneal nerve (CPN) is associated with changes in the motor response of the tibialis anterior (TA) muscle elicited by focal magnetic stimulation of the motor cortex. Motor evoked potentials (MEP) with a stimulation intensity of 125% of the threshold of the relaxed right TA were obtained before, during, and after repetitive electrical stimulation of the CPN (trains of five pulses of 1 ms, at a frequency of 200 Hz, repeated every second with a 30-min duration). The MEP of the TA muscle elicited after repetitive electrical stimulation were increased by 104% (range: 18-263%), and the increase was maintained for up to 110 min (range: 15-110 min) after the end of nerve stimulation. This increase in the MEP of the TA muscle was associated with a decrease in the threshold from the stimulation-response curve. Furthermore, during that period the early component of the TA stretch reflex as well as the latency of the MEP did not significantly change. To further test the origin of the increased MEP, complementary experiments showed that MEP elicited by transcranial electrical stimulation (TES) were also increased, but to a lesser degree (approximately 50%) than MEP elicited by TMS. It can be concluded that short-term nerve repetitive electrical stimulation of the lower extremities in healthy human participants can lead to a long-term increase in the contralateral MEP. As TES is believed to mainly activate the axon and not the soma of the cortical cells, the increased MEP cannot be explained exclusively by changes in the motor cortex cell excitability, but also by changes in subcortical neural structures involved in the excitation of spinal motoneurons. The results of this study allow the speculation that it would be possible to use repetitive electrical stimulation in the rehabilitation of patients with lower limb muscle weakness and spasticity.

The effects of long-term FES-assisted walking on intrinsic and reflex dynamic stiffness in spastic spinal-cord-injured subjects.

The effects of long-term functional electrical stimulation (FES)-assisted walking on ankle dynamic stiffness were examined in spinal cord-injured (SCI) subjects with incomplete motor function loss. A parallel-cascade system identification method was used to identify intrinsic and reflex contributions to dynamic ankle stiffness at different ankle positions while subjects remained relaxed. Intrinsic stiffness dynamics were well modeled by a linear second-order model relating intrinsic torque to joint position. Reflex stiffness dynamics were accurately described by a linear third-order model relating halfwave rectified velocity to reflex torque. We examined four SCI subjects before and after long-term FES-assisted walking (> 16 mo). Another SCI subject, who used FES for only five months was examined 12 mo latter to serve as a non-FES, SCI control. Reflex stiffness decreased in FES subjects by an average of 53% following FES-assisted walking, intrinsic stiffness also dropped by 45%. In contrast, both reflex and intrinsic stiffness increased in the non-FES, SCI control. These findings suggest that FES-assisted walking may have therapeutic effects, helping to reduce abnormal joint stiffness.

The effect of locomotor training combined with functional electrical stimulation in chronic spinal cord injured subjects: walking and reflex studies.

With the new developments in traumatology medicine, the majority of spinal cord injuries sustained are clinically incomplete and the proportion is likely to continue to rise. Thus, it is necessary to continue to develop new treatment and rehabilitation strategies and understand the factors that can enhance recovery of walking following spinal cord injury (SCI). One new development is the use of functional electrical stimulation (FES) device to assist locomotion. The objective of this review is to present findings from some recent studies on the effect of long-term locomotor training with FES in subjects with SCI. Promising results are shown in all outcome measures of walking, such as functional mobility, speed, spatio-temporal parameters, and the physiological cost of walking. Furthermore, the change in the walking behavior could be associated with plasticity in the CNS organization, as seen by the modification of the stretch reflex and changes in the corticospinal projection to muscles of the lower leg. In conclusion, recovery of walking is an increasing possibility for a large number of people with SCI. New modalities of treatment have become available for this population but most still need to be evaluated for their efficacy. This review has focused on FES assisted walking as a therapeutic modality in subjects with chronic SCI, but it is envisaged that the care and recovery of SCI in the early phase of recovery could also be improved.