[Prospective comparison of assessments to evaluate fall risk in a nursing home population]. / Prospektiver Vergleich von Assessments zur Beurteilung der Sturzgefahr bei Pflegeheimbewohnern.

BACKGROUND: Falls represent the main health risk in the over-60 age group. Therefore, evaluation of the individual fall risk and assessment of fall mechanisms are important preventive tools. STUDY QUESTION: The goal of this study was to validate a new posturographic measurement system [Interactive Balance System (IBS)] in terms of fall prediction. MATERIALS AND METHODS: In all, 108 subjects (mean age: 81.9+/-9.5 years) were submitted to the IBS, as well as other fall risk assessment methods [FES-1, Timed-Up-and-Go Test, Performance Oriented Mobility Assessment (Tinetti-Test), Chair-Rising-Test, Tandem stance). The follow-up period of 6 months prospectively recorded all falls using a fall diary. RESULTS: Of the nursing home residents studied, 25 (23%) fell at least once. The posturographic fall index FI(F1&WDI) (sensitivity: 88%) and the Timed-Up-and-Go Test (PPV: 38%) showed the best results regarding sensitivity and positive prediction value (PPV). CONCLUSION: The IBS and the Timed-Up-and-Go Test proved to be the most powerful assessment tools for fall prediction. Furthermore, the IBS is able to provide a purposeful adaption of preventive sensomotoric interventions.

Measured spectral bidirectional reflection properties of four vegetated surfaces.

Spectral bidirectional reflectance values are presented at the 0.52-microm wavelength based on measured values of the radiation field of four vegetated surfaces: savannah, bog, pasture land, and coniferous forest, which cover a wide range of natural vegetated canopies. The results are given as examples of the full set of bidirectional reflectance values which consists of data at seven wavelengths between 0.43microm and 2.20 microm for each of the four surfaces. (From July 1977, the full set of data is available from the author on request.) The data may be applied for calculations of the radiative transfer in the atmosphere with realistic ground properties instead of isotropic albedo values.

Influence of measured reflection properties of vegetated surfaces on atmospheric radiance and its polarization.

Based on measured values of the spectral bidirectional reflection functions of four vegetated surfaces, the influence of their angular anisotropy on the upward and downward emerging radiance and its polarization is calculated. By means of a realistic model of the atmosphere and with the assumption of completely depolarizing reflection properties of the surfaces, results are obtained in dependence of wavelength and solar zenith angle. The angular anisotropy influences considerably the upward emerging radiance. On the degree of polarization and on the downward emerging radiance the anisotropy has negligible to small influence. Due to the angular anisotropy of the reflection properties the spectral albedo depends strongly on the solar zenith angle. This influences upward and downward radiance as well as its degree of polarization. Therefore, for the interpretation of radiation measurements, those spectral albedo values should be used which correspond to the respective solar zenith angle. This is essential especially at longer wavelengths where vegetated surfaces have high spectral albedos.