Reliability of two methods for identifying the timing of medium latency responses in subjects with and without chronic ankle instability.

This study aims to: (1) to compare 2 methods of assessing the timing of medium latency responses (MLR), in regard to intrasession reliability and mean values, in subjects with and without chronic ankle instability (CAI), and (2) to analyze the influence of CAI in timing of MLR and in its reliability. Thirty six athletes with (16) and without (20) CAI participated. Bilateral electromyography of peroneus longus (PL), peroneus brevis (PB), tibialis anterior (TA) and soleus (SOL) muscles was collected during a unilateral sudden inversion perturbation to assess the timing of MLR onset, in both standing and perturbed positions, through a baseline-based method and a peak-response-based method. The group without CAI presented higher relative reliability of SOL and peroneal muscles MLR with the peak response-based method than with the baseline-based method. Compared with the group without CAI and in both methods, the group with CAI presented a delayed and less reliable TA MLR, as well decreased coefficient variation of PL MLR in the uninjured limb. In conclusion, regardless of the method subjects with CAI present delayed and less reliable TA MLR while in subjects without CAI the peak response-based method provides higher reliability.

Short and Medium Latency Responses in Participants With Chronic Ankle Instability.

CONTEXT: The determinant role of medium latency responses (MLRs) during compensatory postural adjustments in postural stability and the lack of clarity about the mechanisms behind chronic ankle instability (CAI) sustain the hypothesis that these postural responses are impaired in this condition. However, to the best of our knowledge, no authors have assessed MLRs in patients with CAI; most of the research regarding compensatory postural adjustments has been directed at the timing of short latency responses (SLRs). OBJECTIVE: To evaluate bilateral compensatory postural responses, including SLRs and MLRs, in response to a unilateral simulated ankle-sprain mechanism in participants with CAI. DESIGN: Case-control study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-four participants with CAI and 20 controls. INTERVENTION(S): Bilateral electromyography of the peroneus longus (PL), peroneus brevis, tibialis anterior (TA), and soleus (SOL) muscles was collected during a unilateral sudden-inversion perturbation (30°). MAIN OUTCOME MEASURE(S): Muscle-onset activations and magnitudes of SLRs and MLRs in the support and perturbed positions. RESULTS: Participants with CAI showed (1) later-onset activation of the TA and SOL in the uninjured limb and bilateral decreases in the magnitude of the TA MLR in the support position, (2) increased magnitude of the PL MLR in the uninjured limb in the support and perturbed positions, and (3) increased magnitude of the PL SLR and MLR in the injured limb in the perturbed position. CONCLUSIONS: Chronic ankle instability was associated with later TA and SOL activation in the uninjured limb and bilaterally decreased magnitude of the TA MLR in the support position.

Unstable angina as initial manifestation of Wegener granulomatosis: case report.

Wegener granulomatosis (WG) is a necrotizing vasculitis that usually affects the respiratory tract, in association with kidney disease. Cardiac involvement is rare and silent in most cases, only becoming evident in necropsy studies. The authors report the case of a patient with WG, whose unstable angina was the first clinical manifestation, although the patient had suffered a previous unrecognized myocardial infarction. In most cases cardiovascular disease is clinically silent, but there may be symptoms indicating involvement of the coronary arteries, pericardium, myocardium, endocardium, cardiac valves, conduction system or thoracic great vessels. In most cases cardiac manifestations appear late in the natural history of GW. In the case reported, cardiac symptoms appeared as the first manifestation of the disease, a situation which we were unable to find described in the literature. The authors review the literature on cardiac manifestations of WG, together with recommendations for diagnosis and follow-up of this disease.