Sleep studies: which technologies?

Use of actigraphy for assessment in pediatric sleep research

The use of actigraphs, or ambulatory devices that estimate sleep-wake patterns from activity levels, has become common in pediatric research. Actigraphy provides a more objective measure than parent-report, and has gained popularity due to its ability to measure sleep-wake patterns for extended periods of time in the child's natural environment. The purpose of this review is: 1) to provide comprehensive information on the historic and current uses of actigraphy in pediatric sleep research; 2) to review how actigraphy has been validated among pediatric populations; and 3) offer recommendations for methodological areas that should be included in all studies that utilize actigraphy, including the definition and scoring of variables commonly reported. The poor specificity to detect wake after sleep onset was consistently noted across devices and age groups, thus raising concerns about what is an "acceptable" level of specificity for actigraphy. Other notable findings from this review include the lack of standard scoring rules or variable definitions. Suggestions for the use and reporting of actigraphy in pediatric research are provided.

Subjective sleep quality in premenstrual syndrome

Premenstrual syndrome (PMS) is a cyclical disorder observed in late luteal phase and presenting with behavioral changes that can affect interpersonal relationships and normal daily activity. Sleep disturbances are also common. The aim of this study is to investigate the relationship between PMS and subjective sleep quality with Pitsburg Sleep Quality Index (PSQI) in the Medical Academy students, whom have considerable information about menstruation. PMS was detected with "Premenstrual Syndrome Scale", and PSQI was used to evaluate subjective sleep quality. Chi-square test and Kendall's rank correlation analysis were used in statistical analysis. p values (p < 0.05) were considered as statistical significant. Poor sleep quality was found in the 75.6% of the participants with PMS, and 58.8% of the participants without PMS (p < 0.05). Only component 5 (sleep disorder component) of the PSQI components revealed statistically significant difference (1.7 ± 0.6 in participants with PMS, and 1.5 ± 0.6 without PMS, p < 0.05). There was a positive correlation between total PSQI score and all of its' components, except component 6 (sleeping pill usage component) (p < 0.05). The strongest association was found to be in the component 5 (r = 0.528; p = 0.0001). Results of our study suggested the poor sleep quality due to sleep disorders in women with PMS.

Invalidity of one actigraphy brand for identifying sleep and wake among infants

STUDY OBJECTIVES

Few commercially available brands of actigraphs (ACT) have been subjected to rigorous validation with infant participants. The purpose of this study was to examine the agreement between concurrent polysomnography (PSG) and one brand of ACT (AW-64, Mitter Co. Inc.) using appropriate statistical techniques among a sample of healthy infants.

METHODS

Twenty-two healthy infants (14.1+/-0.6 months) had one night of ankle ACT recording during research PSG at Kosair Children's Hospital Sleep Research Center in Louisville, Kentucky. Macroanalyses were conducted using the Bland-Altman concordance technique to assess agreement between total sleep time (TST) and wake after sleep onset (WASO) simultaneously measured by PSG and ACT, using two ACT algorithm settings. Microanalyses were also calculated to examine sensitivity, specificity, and accuracy of ACT within each PSG-identified sleep state. Correlations were calculated between PSG-identified arousals and the discrepancies between ACT and PSG.

RESULTS

The Bland-Altman concordance technique revealed that ACT underestimated TST by 72.25 (SD=61.48) minutes and by > or = 60 min among 54.55% of infants. Furthermore, ACT overestimated WASO by 13.85 (SD=30.94) minutes and by > or = 30 min among 40.91% of infants. Sensitivity, specificity, and accuracy analyses revealed that ACT adequately identified sleep, but poorly identified wake. PSG and ACT discrepancies were positively associated with PSG-identified arousals (r=.45).

CONCLUSIONS

Improved device and/or software development is needed before the AW-64 can be considered a valid method for identifying infant sleep and wake.

Interpretation of the polysomnogram in children

Polysomnography (PSG) is a useful tool for the diagnosis of sleep disorders in children. This multichannel study obtains information about sleep architecture, respiratory effort, movements during sleep, respiratory events, and gas exchange to facilitate the evaluation of children who have disrupted sleep or suspected SDB. Children should be studied in a sleep laboratory equipped for and staffed with personnel comfortable with and experienced in the performance of PSG in children. The scoring and interpretation of PSG differs in children and adults. The pediatric PSG should be interpreted by a pediatric professional knowledgeable in normal development and sleep disorders in children.