Johannes Stahl

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PURPOSE To determine the distribution of perceived ability for independent mobility in people who are at various stages of retinitis pigmentosa (RP). METHODS A questionnaire was developed to ask subjects to rate how difficult they found each of 35 mobility situations if they had no assistance. The scale was 1 (no difficulty) to 5 (extreme difficulty). In(More)
This study evaluated the effects of retinitis pigmentosa (RP) on mobility performance (walking speed, mobility incidents) under conditions of normal and reduced illumination and on self-perceived mobility difficulties. The results showed that RP subjects travel more slowly than the normally sighted subjects, that both normally sighted and RP subjects travel(More)
PURPOSE The purpose of this study was to determine whether persons with advanced vision impairment, when walking an unfamiliar route, visually sample the environment in a different manner than do persons with normal vision. METHODS Direction of gaze was measured in six persons with retinitis pigmentosa (RP) and in three persons with normal vision as they(More)
PURPOSE To determine whether retinitis pigmentosa (RP) increases the mental effort required for walking. METHODS A dual-task methodology was used; walking speed and reaction time (RT) to randomly emitted tones were measured in 13 persons with RP and 29 persons with normal vision. Measures of RT were used to estimate the mental effort required for walking.(More)
Given the decline in dental caries incidence in preteens and young teenagers in the United States, a study of the incidence of dental caries in young adults (17-23 years) was conducted to provide a descriptive epidemiologic picture of this "new" natural history of dental caries in the late and post-teenage years. A retrospective study was performed(More)
PURPOSE A novel rotational IMRT (rIMRT) technique using burst delivery (continuous gantry rotation with beam off during MLC repositioning) is investigated. The authors evaluate the plan quality and delivery efficiency and accuracy of this dynamic technique with a conventional flat 6 MV photon beam. METHODS Burst-delivery rIMRT was implemented in a(More)
Robust automatic speech recognition in adverse environments is a challenging task. We address the 4 CHiME challenge [1] multi-channel tracks by proposing a deep eigenvector beamformer as front-end. To train the acoustic models, we propose to supplement the beamformed data by the noisy audio streams of the individual microphones provided in the real set.(More)