1192 The Accuracy of a Novel Sleep Ring Device for Estimating Sleep Onset with Good and Poor Sleepers

Introduction

THIM is a new ring-like sleep device that, if found to accurately measure sleep onset, could be used for a variety of clinical purposes. These include administering a brief but effective treatment for insomnia called Intensive Sleep Retraining, facilitating the optimal 10-minute power nap, and administering Multiple Sleep Latency Tests (MSLTs) outside of the sleep laboratory. This study assessed the accuracy of THIM for measuring sleep onset latency compared to polysomnography (PSG).

Methods

Twenty healthy individuals aged 23.6 years (SD = 4.89) underwent overnight PSG recording whilst using THIM on two nights in the sleep laboratory, one week apart. On each night, participants completed sleep onset trials for four hours whilst monitored via PSG. In these trials, participants attempted to fall asleep whilst responding to vibrations emitted from THIM. Once they failed to respond to two consecutive stimuli, THIM woke them with an intense vibration. Participants had a short break before attempting the next trial.

Results

On average, THIM overestimated sleep onset on the first night by 0.24 minutes (SD = 0.90). On the second night, THIM overestimated sleep onset by 0.82 minutes (SD = 1.31) and this discrepancy was not significantly different to that obtained on the first night, p = .08. The accuracy of THIM did not differ between good sleepers (Insomnia Severity Index (ISI) score < 7) or poor sleepers (ISI score 8-15), p = .98.

Conclusion

The findings suggest that THIM is accurate at estimating sleep onset latency for both good and poor sleepers. The next step is to test THIM outside of the laboratory environment. The goal is to develop an accurate yet practical device that can translate laboratory-based procedures to the home environment, to the benefit of patients and clinicians wanting to improve sleep.

Support

The project was funded in-part by the manufacturers of THIM, Re-Time Pty. Ltd., with additional funding provided by Flinders University.

A discrepancy between the instantaneous and the overall collection efficiency of the fenwal CS3000 for peripheral blood stem cell apheresis

The collection efficiency (CE) of the Fenwall CS3000 continuous flow blood cell separator in the apheresis of peripheral blood stem cells during haemopoietic recovery following myelosuppressive chemotherapy was analysed. Ninety-three apheresis were performed in 19 patients using procedure 3 on the Fenwal CS3000. The overall CE was calculated from the pre-apheresis cell counts and the stated blood volume processed. Instantaneous CE was calculated from cell counts in the inlet and return lines. The overall mononuclear cell and granulocyte-macrophage colony forming unit CE were 64.0% and 55.8%, respectively, significantly lower than the instantaneous CEs of 94.5% and 95.4%, respectively (P = 0.0001, t test, for both comparisons). Three factors unrelated to machine performance contributed to the lower overall CE despite a high instantaneous CE: (1) A fall in the patient's mononuclear cell counts during apheresis leading to an overestimation of the cells available for collection, (2) dilution of blood by anti-coagulant, and (3) the operational dead space of the Fenwal CS3000. The overall CE corrected for these 3 factors approximated the instantaneous CE closely. Thus there is little room for further enhancement of machine performance because the Fenwal CS3000 is already operating with a very high instantaneous CE. To achieve major improvement in the yield of peripheral blood stem cell harvests, more effective mobilization protocols and better timing of apheresis are required.

The natural history of chronic middle ear disease in Australian Aboriginals: a cross-sectional study

One hundred and sixty-three Australian Aboriginals, who were aged from four months to 60 years, were examined clinically and otologically. Audiometric tests were completed on 110 of these subjects. On the assumptions that the aural health of these people has remained stable for many years, the cross-sectional data which were obtained have been used to infer the natural history of ear disease. Seromucinous otitis media is manifest as a disease of early childhood, which recovers spontaneously in most cases and has no obvious sequelae. Perforated tympanic membranes likewise seem to heal spontaneously in the majority of cases. The evidence suggests that hearing loss is the main problem and treatment should be directed towards the level of hearing loss and its effects.

Open-ended tympanometric screening: A new concept

We introduce the concept of open-ended, successive-day, tympanometric screening. In impedance screening of children for middle ear disorders, there is a serious risk of over-referral if decisions are made on the basis of a single tympanogram. Serial tympanometric studies of Australian aboriginal children show that, whereas the type B tympanogram is usually stable, type A and type C patterns are prone to vary from day to day, inviting inappropriate referral decisions unless the classifications are confirmed by tests on successive days.