Altering the rhythm of target and background talkers differentially affects speech understanding.

Three experiments investigated listeners' ability to use speech rhythm to attend selectively to a single target talker presented in multi-talker babble (Experiments 1 and 2) and in speech-shaped noise (Experiment 3). Participants listened to spoken sentences of the form "Ready [Call sign] go to [Color] [Number] now" and reported the Color and Number spoken by a target talker (cued by the Call sign "Baron"). Experiment 1 altered the natural rhythm of the target talker and background talkers for two-talker and six-talker backgrounds. Experiment 2 considered parametric rhythm alterations over a wider range, altering the rhythm of either the target or the background talkers. Experiments 1 and 2 revealed that altering the rhythm of the target talker, while keeping the rhythm of the background intact, reduced listeners' ability to report the Color and Number spoken by the target talker. Conversely, altering the rhythm of the background talkers, while keeping the target rhythm intact, improved listeners ability to report the Color and Number spoken by the target talker. Experiment 3, which embedded the target talker in speech-shaped noise rather than multi-talker babble, similarly reduced recognition of the target sentence with increased alteration of the target rhythm. This pattern of results favors a dynamic-attending theory-based selective-entrainment hypothesis over a disparity-based segregation hypothesis and an increased salience hypothesis.

Screening for catastrophic neck injuries in sports.

The cervical spine is prone to injury due to the structure of the articulating vertebrae at the level of C4-C6, where the spinal cord occupies more of the spinal canal. Cervical spine injuries can occur in all sports and all ages. Participation in contact sports certainly increases the possibility of cervical spine injuries. In screening for catastrophic neck injuries it is vital to examine incidence and injury surveillance statistics in sports. These data can help determine sport-specific preponderance of catastrophic injury. Screening methods for predisposition to catastrophic cervical spine injuries include a concise history, physical examination, and radiographic methods. There is currently no universal classification system utilizing imaging of the cervical spine that has been validated as a screening method for catastrophic neck injuries.