Blinks and saccades as indicators of fatigue in sleepiness warnings: looking tired?

The present study examines changes in a variety of oculomotoric variables as a function of increasing sleepiness in 129 participants, who have been passed through a broad range of subjective alertness. Up to now, spontaneous eye blinks are the most promising biosignal for in-car sleepiness warnings. Reviewing the current literature on eye movements and fatigue, experimental data are provided including additional indicative oculomotoric parameters; inter-individual differences in the experiments were also assessed. Here, self-rated alertness decreased over six steps on average and proved itself a reliable measurement. Regarding oculomotoric parameters, blink duration, delay of lid reopening, blink interval and standardised lid closure speed were identified as the best indicators of subjective as well as objective sleepiness. Saccadic parameters and fixation durations also showed specific changes with increasing sleepiness. Substantial inter-individual differences in all of these variables were illustrated. Oculomotoric parameters were linked to three different components of sleepiness while driving: a) deactivation; b) decreasing attention, resulting in disinhibition of spontaneous blinks and reflexive saccades; c) increasing attempts of self-activation. Finally, implications for the development of drowsiness detection devices were discussed

Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency

© 2014, Springer-Verlag Berlin Heidelberg. Purpose: Meniscal injury resulting in segmental loss of meniscal tissue is a major risk factor for the development of osteoarthritis. Tissue engineering strategies have provided scaffolds for meniscal regeneration in order to establish a treatment option for patients with limited opportunities for meniscal reconstruction. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 2 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. Methods: Eighteen patients were treated with arthroscopic implantation of an ActiFit® (Orteq Sports Medicine) polyurethane meniscal scaffold for meniscus deficiency of the medial meniscus. Patients were followed up at 6, 12, and 24 months. Clinical outcome was assessed using patient-reported outcome scores (KOOS, KSS, UCLA activity scale, VAS for pain). Radiological outcome was assessed using MRI at 6, 12, and 24 months by evaluating scaffold morphology, scaffold integration, and additional joint injury, as well as joint inflammation. Results: Eighteen patients with a median age of 32.5 years (range 17–49) were enrolled. Statistically significant improvements were present in all patients, but one at 2 years compared to baseline in all categories. Complete resorption of the scaffold occurred in one patient representing a failure to treatment. MRI showed abnormal signal intensity of the scaffold when compared to residual meniscal tissue but without synovitis or joint inflammation. Extrusion of the scaffold was present in four patients. No correlation between scaffold extrusion and clinical outcome was observed. Conclusion: Arthroscopic implantation of a polyurethane meniscal scaffold in patients with chronic segmental medial meniscus deficiency is not only a safe procedure but leads to good clinical results at a 2-year follow-up. Scaffold extrusion did not appear to affect clinical outcome. Level of evidence: IV