Effects of focal vibration on bone mineral density and motor performance of postmenopausal osteoporotic women.

AIM: This randomized double blind controlled study is aimed at determining the effect of repeated vibratory stimuli focally applied to the contracted quadriceps muscles (repeated muscle vibration=rMV) on bone mineral density, leg power and balance of postmenopausal osteoporotic women. METHODS: The study has been conducted on 40 voluntary postmenopausal osteoporotic women, randomised at 2 groups for rMV treatment and for control. The treatment group underwent rMV (100Hz, 300-500 µm; three applications per day, each lasting 10-minutes, for 3 consecutive days) applied to voluntary contracted quadriceps (VC=vibrated and contracted group). The control group, received a sham stimulation on contracted quadriceps (NV=non vibrated group). Bone mineral density T-score of proximal femur of the participants, was evaluated in two weeks before and 360 days after intervention; body balance and explosive leg power were measured 1 day before, 30 days and 360 days after treatment. RESULTS: VC group T-score at one year didn't change significantly relative to baseline values (pretreatment: -2.61±0.11, post-treatment -2.62±0.13); conversely in NV subjects T-score decreased significantly from -2.64 ± 0.15 SD down to -2.99 ± 0.28 SD. A significant improvement of balance and explosive leg power was observed only in VC group at 30 and 360 days after the intervention. CONCLUSION: We conclude that rMV is a safe, short-lasting and non-invasive treatment that can significantly and persistently improve muscle performance and can effectively counteract progressive demineralisation in postmenopausal and osteoporotic women.

Prolonged asymmetric vestibular stimulation induces opposite, long-term effects on self-motion perception and ocular responses.

Self-motion perception and the vestibulo-ocular reflex (VOR) were investigated in healthy subjects during asymmetric whole body yaw plane oscillations while standing on a platform in the dark. Platform oscillation consisted of two half-sinusoidal cycles of the same amplitude (40°) but different duration, featuring a fast (FHC) and a slow half-cycle (SHC). Rotation consisted of four or 20 consecutive cycles to probe adaptation further with the longer duration protocol. Self-motion perception was estimated by subjects tracking with a pointer the remembered position of an earth-fixed visual target. VOR was measured by electro-oculography. The asymmetric stimulation pattern consistently induced a progressive increase of asymmetry in motion perception, whereby the gain of the tracking response gradually increased during FHCs and decreased during SHCs. The effect was observed already during the first few cycles and further increased during 20 cycles, leading to a totally distorted location of the initial straight-ahead. In contrast, after some initial interindividual variability, the gain of the slow phase VOR became symmetric, decreasing for FHCs and increasing for SHCs. These oppositely directed adaptive effects in motion perception and VOR persisted for nearly an hour. Control conditions using prolonged but symmetrical stimuli produced no adaptive effects on either motion perception or VOR. These findings show that prolonged asymmetric activation of the vestibular system leads to opposite patterns of adaptation of self-motion perception and VOR. The results provide strong evidence that semicircular canal inputs are processed centrally by independent mechanisms for perception of body motion and eye movement control. These divergent adaptation mechanisms enhance awareness of movement toward the faster body rotation, while improving the eye stabilizing properties of the VOR.

Focal vibration of quadriceps muscle enhances leg power and decreases knee joint laxity in female volleyball players.

AIM: This double-blind randomized controlled study aims at determining the effect of repeated muscle vibration (rMV) on explosive and reactive leg power and on knee laxity of female volleyball players. METHODS: Eighteen voluntary volleyball athletes, belonging to the same senior regional level team (age=22.7 ± 3 years, height=180.3 ± 5 cm, mass= 64 ± 4 kg) were assigned to three groups (N.=6) for vibration on contracted quadriceps (VC), vibration on relaxed muscle (VR), and sham vibration (NV), respectively. Intervention consisted in 3 rMV sessions performed in 3 consecutive days. In each session, 100 Hz, 300-500 µm amplitude vibratory stimuli were bilaterally delivered to the quadriceps in three consecutive 10-minutes applications. Explosive and reactive leg power and knee joint laxity were evaluated 1 day before, and 1, 30, and 240 days after intervention. RESULTS: In VC group, explosive and reactive leg power increased respectively by ~16% and ~9% at 1 day, by ~19% and ~11% at 30 days and by ~26% and ~13% at 240 days, concomitantly knee laxity decreased by ~6%, ~15% and ~18% at the same times. These changes were significantly larger than in the other groups, in which leg power increment and knee joint laxity reduction remained close to ~3%, ~5% and ~10% at 1, 30 and 240 days, respectively. CONCLUSION: Combined bilateral voluntary contraction and rMV of the quadriceps muscles is a short-lasting, non-invasive technique that can significantly and persistently improve muscle performance and knee laxity in volleyball women players.

Head position modulates optokinetic nystagmus.

Orientation and movement relies on both visual and vestibular information mapped in separate coordinate systems. Here, we examine how coordinate systems interact to guide eye movements of rabbits. We exposed rabbits to continuous horizontal optokinetic stimulation (HOKS) at 5°/s to evoke horizontal eye movements, while they were statically or dynamically roll-tilted about the longitudinal axis. During monocular or binocular HOKS, when the rabbit was roll-tilted 30° onto the side of the eye stimulated in the posterior â†’ anterior (P â†’ A) direction, slow phase eye velocity (SPEV) increased by 3.5-5°/s. When the rabbit was roll-tilted 30° onto the side of the eye stimulated in the A â†’ P direction, SPEV decreased to ~2.5°/s. We also tested the effect of roll-tilt after prolonged optokinetic stimulation had induced a negative optokinetic afternystagmus (OKAN II). In this condition, the SPEV occurred in the dark, "open loop." Modulation of SPEV of OKAN II depended on the direction of the nystagmus and was consistent with that observed during "closed loop" HOKS. Dynamic roll-tilt influenced SPEV evoked by HOKS in a similar way. The amplitude and the phase of SPEV depended on the frequency of vestibular oscillation and on HOKS velocity. We conclude that the change in the linear acceleration of the gravity vector with respect to the head during roll-tilt modulates the gain of SPEV depending on its direction. This modulation improves gaze stability at different image retinal slip velocities caused by head roll-tilt during centric or eccentric head movement.

Contribution of eye position to movement perception.

OBJECTIVE: To investigate the influence of gaze eccentricity on movement perception during asymmetric vestibular stimulation. MATERIAL AND METHODS: Subjects (n = 10) were placed on a rotating platform and oscillated asymmetrically in the dark. Subjects were asked to reproduce with a pointer the location in space of a light spot that was turned off at the beginning of the oscillation. The target was presented in centric and eccentric (0 degrees, 20 degrees and 40 degrees) positions. RESULTS: In the centric position a large shift from the real position of the target was observed in the opposite direction to that of the faster vestibular stimulation. The shift increased when the target was placed eccentrically toward the slower vestibular stimulation side and decreased when it was placed in the opposite direction. CONCLUSION: The dependence of rotation perception on the target position suggests that the eye deviation, imposed by the eccentricity of the target, is able to influence the perception of body movement and may modulate the internal reference frame.

Prostaglandin E1 for treatment of erectile dysfunction.

BACKGROUND: Erectile dysfunction (ED), the inability to achieve or maintain an erection sufficient for satisfactory sexual activity, is one of the most common sexual dysfunctions in men. ED may have a dramatic impact on the quality of life of many men and their partners. OBJECTIVES: The aim of this systematic review was to evaluate and summarise the effectiveness and safety of PGE1 in the treatment of erectile dysfunction. SEARCH STRATEGY: We searched the Cochrane MS Group Trials Register (June 2003), the Cochrane Central Register of Controlled Trials (issue 2, 2003), MEDLINE (January 1966 - June 2003), EMBASE (January 1988 - June 2003) and reference lists of articles. We also undertook handsearching and contacting trialists and pharmaceutical companies. SELECTION CRITERIA: All unconfounded, double blind, randomised controlled trials comparing PGE1 and placebo treatment in participants with ED of different aetiology were considered. Primary outcomes were: (a) patient and partner satisfaction measured by means of a self-assessment; (b) quality of life and (c) safety assessment. Both parallel group and cross-over design trials were considered for inclusion. DATA COLLECTION AND ANALYSIS: All the reviewers independently selected articles for inclusion, assessed the trials' quality and extracted the data. Study authors were contacted for additional information. MAIN RESULTS: Four trials involving 1.873 people, heterogeneous with respect to aetiology of ED, were included. Study design was two cross-over and two parallel group trials. Only the latter provided adequate data for meta-analyses. PGE1 was effective during follow-up in the "at least one successful intercourse" outcome (Peto Odds Ratio, OR 7.22, 95% CI. 5.68-9.18) and "number of successful intercourse/number of PGE1 administrations" (Peto Odds Ratio, OR 6.46, 95% CI. 5.95-7.01). One cross-over study reported "at least one successful intercourse" in 63.6% of participants with at least one dose of PGE1 (P < 0.01 for each active dose versus placebo). In the other cross-over study, only one of three treatment groups conducted a self-evaluation (55.5%: "good" or "excellent" response). Adverse effects were most frequent in the treated groups and occurred more often and intensely as doses increased. Penile pain (Peto OR 7.39, 95% CI. 5.40-10.12) and minor urethral trauma (Peto OR 3.79, 95% CI. 1.88-7.65) were predominant. REVIEWERS' CONCLUSIONS: PGE1 was beneficial for many participants with ED of different aetiology. Adverse effects were proportional to dosage, albeit never serious. The use of PGE1 in ED could have been better interpreted if its effectiveness were compared by aetiology and with different forms of administrations, a longer follow-up were considered and more emphasis given to patient/partner relationships and quality of life.