[Wearables in the treatment of neurological diseases-where do we stand today?] / "Wearables" in der Behandlung neurologischer Erkrankungen ­ wo stehen wir heute?

Fitness and lifestyle trackers raise the awareness for wearable sensors in medical applications for clinical trials and healthcare. Various functional impairments of patients with neurological diseases are an ideal target to generate wearable-derived and patient-centered parameters that have the potential to support prevention, prediction, diagnostic procedures and therapy monitoring during the clinical work-up; however, substantial differences between clinical grade wearables and fitness trackers have to be acknowledged. For the application in clinical trials or individualized patient care distinct technical and clinical validation trials have to be conducted. The different test environments under laboratory conditions during standardized tests or under unsupervised home monitoring conditions have to be included in the algorithmic processing of sensor raw data in order to enable a clinical decision support under real-life conditions. This article presents the general understanding of the technical application for the most relevant functional impairments in neurology. While wearables used for sleep assessment have already reached a high level of technological readiness due to the defined test environment (bed, sleep), other wearable applications, e.g. for gait and mobility during home monitoring require further research in order to transfer the technical capabilities into real-life patient care.

Self-Powered Multiparameter Health Sensor.

Wearable health sensors are about to change our health system. While several technological improvements have been presented to enhance performance and energy-efficiency, battery runtime is still a critical concern for practical use of wearable biomedical sensor systems. The runtime limitation is directly related to the battery size, which is another concern regarding practicality and customer acceptance. We introduced ULPSEK-Ultra-Low-Power Sensor Evaluation Kit-for evaluation of biomedical sensors and monitoring applications (http://ulpsek.com). ULPSEK includes a multiparameter sensor measuring and processing electrocardiogram, respiration, motion, body temperature, and photoplethysmography. Instead of a battery, ULPSEK is powered using an efficient body heat harvester. The harvester produced 171 W on average, which was sufficient to power the sensor below 25 C ambient temperature. We present design issues regarding the power supply and the power distribution network of the ULPSEK sensor platform. Due to the security aspect of self-powered health sensors, we suggest a hybrid solution consisting of a battery charged by a harvester.

Evaluation of techniques for estimating the power spectral density of RR-intervals under paced respiration conditions.

Heart rate variability (HRV) analysis is increasingly used in anaesthesia and intensive care monitoring of spontaneous breathing and mechanical ventilated patients. In the frequency domain, different estimation methods of the power spectral density (PSD) of RR-intervals lead to different results. Therefore, we investigated the PSD estimates of fast Fourier transform (FFT), autoregressive modeling (AR) and Lomb-Scargle periodogram (LSP) for 25 young healthy subjects subjected to metronomic breathing. The optimum method for determination of HRV spectral parameters under paced respiration was identified by evaluating the relative error (RE) and the root mean square relative error (RMSRE) for each breathing frequency (BF) and spectral estimation method. Additionally, the sympathovagal balance was investigated by calculating the low frequency/high frequency (LF/HF) ratio. Above 7 breaths per minute, all methods showed a significant increase in LF/HF ratio with increasing BF. On average, the RMSRE of FFT was lower than for LSP and AR. Therefore, under paced respiration conditions, estimating RR-interval PSD using FFT is recommend.

A review of 13 years of experience with endoscopic forehead-lift.

OBJECTIVE: To conduct objective quantitative and qualitative evaluations of the long-term result in endoscopic forehead-lift. METHODS: Medical charts of 143 patients who underwent endoscopic forehead-lift between 1994 and 2007 were reviewed for postoperative complications and the duration of complaints. Patients received a questionnaire to evaluate satisfaction and social restriction after surgery. Objective photographic preoperative and postoperative eyebrow-to-eye distances in a relaxed position and during muscle contractions were obtained. RESULTS: A total of 98 patients (69% response; mean follow-up, 38 months) showed high satisfaction (score, 7.1 of 10). In a relaxed position, mean midpupil-to-eyebrow elevation was 5.6 mm after surgery, with significant eyebrow symmetry between the left and right eyes (P < .05), and showed significant influence of time (P = .005) on persisting eyebrow elevation, with a decrease of almost 1 mm per year. Measurements during muscle contraction showed no relevant differences. CONCLUSION: Endoscopic forehead-lift enables long-lasting results with highly satisfied patients.

Effects of substrate annealing on the gold-catalyzed growth of ZnO nanostructures.

The effects of thermal substrate pretreatment on the growth of Au-catalyzed ZnO nanostructures by pulsed laser deposition are investigated. C-plane sapphire substrates are annealed prior to deposition of a thin Au layer. Subsequent ZnO growths on substrates annealed above 1,200°C resulted in a high density of nanosheets and nanowires, whereas lower temperatures led to low nanostructure densities. Separate Au film annealing experiments at 700°C showed little variation in the size and density of the Au catalyst droplets with substrate annealing temperature. The observed variation in the density of nanostructures is attributed to the number of surface nucleation sites on the substrate, leading to a competition between nucleation promoted by the Au catalyst and surface nucleation sites on the rougher surfaces annealed below 1,200°C.

The free vascularized fibular epiphyseal transfer: long-term results of wrist reconstruction in young patients.

To date, the dominant blood supply to the head of the fibula and to the growth plate is known to be the anterior tibial artery. The peroneal artery had been used before, among other donor pedicles, for microvascular transfers of this epiphyseal region. This study presents the long-term results of this now obsolete pedicle and compares them to other reports in the literature. Follow-up was performed in 1996 and in 2003 with six patients who underwent wrist reconstruction in the 1980s. Procedures were performed following one resection of a malignant synovialoma, two traumatic hand amputations, and three radial aplasias. Evaluation was performed with functional and radiographic examinations. Three cases that were examined in 2003 are presented in detail. The study shows that if growth plates are closed at the time of procedure or the transplanted fibula is long enough to ensure anastomotic flow between metaphyseal and epiphyseal vessels, results are good. If any of these two conditions is not fulfilled, vascular supply to the epiphysis is insufficient. Long bone deviation or bone necrosis will result. These results confirm clinically current knowledge about the epiphyseal and metaphyseal blood supply to the fibula.