ABSTRACT
Objectives: To determine whether spindle chirp and other sleep oscillatory features differ in young children with and without autism. Methods: Automated processing software was used to re-assess an extant set of polysomnograms representing 121 children (91 with autism [ASD], 30 typically-developing [TD]), with an age range of 1.35-8.23 years. Spindle metrics, including chirp, and slow oscillation (SO) characteristics were compared between groups. SO and fast and slow spindle (FS, SS) interactions were also investigated. Secondary analyses were performed assessing behavioural data associations, as well as exploratory cohort comparisons to children with non-autism developmental delay (DD). Results: Posterior FS and SS chirp was significantly more negative in ASD than TD. Both groups had comparable intra-spindle frequency range and variance. Frontal and central SO amplitude were decreased in ASD. In contrast to previous manual findings, no differences were detected in other spindle or SO metrics. The ASD group displayed a higher parietal coupling angle. No differences were observed in phase-frequency coupling. The DD group demonstrated lower FS chirp and higher coupling angle than TD. Parietal SS chirp was positively associated with full developmental quotient. Conclusions: For the first time spindle chirp was investigated in autism and was found to be significantly more negative than in TD in this large cohort of young children. This finding strengthens previous reports of spindle and SO abnormalities in ASD. Further investigation of spindle chirp in healthy and clinical populations across development will help elucidate the significance of this difference and better understand this novel metric.
ABSTRACT
We compared a "cardiac profile" test with standard creatine kinase (CK) and lactic dehydrogenase (LD) electrophoresis in 798 cases of possible acute myocardial infarction (MI). The cardiac profile enzyme screen (CK-B, CK, LD) used on 495 patients who came to the emergency department with chest pain suggestive of acute MI but without diagnostic ECG changes. Instead of admission to the coronary care unit, they were placed on observation status (Chest Pain Evaluation Unit) for a period up to 20 hours (average 11.1 hours). Using the results of the cardiac profile, 327 were able to be sent home. Of the 168 patients admitted, only 30 (18%) had subsequent enzyme evidence of myocardial necrosis. Use of the chest pain evaluation unit resulted in an 80% reduction in cost of ruling out acute MI for the 327 patients not admitted.
