Diagnosing and managing spinal injury in patients with ankylosing spondylitis.

BACKGROUND: Individuals with ankylosing spondylitis are at an increased risk of vertebral fractures. These are often unstable, leading to primary and secondary neurological injury and conferring high levels of morbidity and mortality. Fractures in these patients can occur after minimal trauma and are easily missed, with potentially disastrous consequences. OBJECTIVES: To educate health professionals who may be involved in the initial assessment and management of ankylosing spondylitis patients with possible spinal injuries, despite not being spinal specialists. CASE REPORTS: We present three cases from our own hospital, which illustrate the pitfalls associated with traumatic spinal injury in ankylosing spondylitis. Case 1 shows why delayed presentation of spinal injury is common, as well as demonstrating the need for multiple imaging modalities in some patients. Case 2 is an example of primary neurological injury in this patient group, and case 3 highlights the risk of secondary neurological injury, as well as the effect of multiple comorbidities on patient outcomes. CONCLUSIONS: It is important that staff in the Emergency Department have an understanding of the extreme caution that is needed in the management of possible spinal injuries in patients with or suspected of having ankylosing spondylitis.

Sequential streaming due to manipulation of interaural time differences.

The effect of apparent spatial location on sequential streaming was investigated by manipulating interaural time differences (ITDs). The degree of obligatory stream segregation was inferred indirectly from the threshold for detecting a rhythmic irregularity in an otherwise isochronous sequence of interleaved "A" and "B" tones. Stimuli were bandpass-filtered harmonic complexes with a 100-Hz fundamental. The A and B tones had equal but opposite ITDs of 0, 0.25, 0.5, 1, or 2 ms and had the same or different passbands. The passband ranges were 1250-2500 Hz and 1768-3536 Hz in experiment 1, and 353-707 Hz and 500-1000 Hz in experiment 2. In both experiments, increases in ITD led to increases in threshold, mainly when the passbands of A and B were the same. The effects were largest for ITDs above 0.5 ms, for which rhythmic irregularities in the timing of the A or B tones alone may have disrupted performance. It is concluded that the differences in apparent spatial location produced by ITD have only weak effects on obligatory streaming.