Saccadic fatigability in the oculomotor system.

BACKGROUND: Fatigue is one of the most common and disabling symptoms in multiple sclerosis (MS), but challenging to quantify. This prospective study investigated if repeated saccadic eye movements enable measurement of oculomotor fatigability and can reflect on perceived fatigue in MS. METHODS: A standardized infrared oculography protocol (DEMoNS) was used for quantifying saccades in MS patients and healthy controls which included a first and a repeated pro-saccadic task (FPT and RPT). Saccadic peak velocity, latency, gain, area under the curve (AUC) and peak velocity divided by amplitude (Pv/Am) were calculated in both tasks. Perception based fatigue was assessed using the Checklist Individual Strength and the Neurological Fatigue Index (NFI). Linear regression models were used for assessing the relation between saccadic parameters and perceived fatigue. RESULTS: This study included 181 MS patients and 58 healthy controls subjects. From FPT to RPT, there were significant changes in saccadic parameters. Latency of both tasks was significantly related to NFI summary score (FPT: ß = 0.022, p = .049, RPT: ß 0.023, p = .021). These relationships were weakened after adjustment for Expanded Disability Status score (p > .05). There was however no significant group difference in changes in saccadic parameters. CONCLUSIONS: This study presents an objective and reproducible method for measuring saccadic fatigability. Saccadic fatigability was found to be of limited use in MS, and should be tested in conditions affecting ocular muscles or the neuromuscular junction.

The clinical recovery of fattening pigs from respiratory disease after treatment with two injectable oxytetracycline formulations.

A double blind randomized clinical trial was performed with pigs suffering from clinical respiratory disease. The goal of the trial was to test the null hypothesis that the clinical recovery after treatment with two oxytetracycline injectables with different pharmacokinetic profiles (high peak concentration and low persistence versus low peak concentrations and long persistence) was similar. Fattening pigs (n = 529) were treated intramuscularly with either product A or product B at a dose of 20 mg OTC per kg b.w. when they showed signs of acute pneumonia, i.e., coughing, tachypnoea or dyspnoea combined with a rectal temperature of 40 degrees C or higher. When necessary, treatment was given again after 3 and/or 6 days. Both treatments resulted in a rapid fall in mean temperature and an improved clinical condition. In this trial no significant differences were found in clinical recovery between the two therapies as measured by group mean temperature, number of pigs requiring retreatment, and time to recovery. The conclusion that there was no important difference in clinical recovery between the treatment groups was made with a power of at least 90%.