Degree of pineal calcification (DOC) is associated with polysomnographic sleep measures in primary insomnia patients

Mahlberg, Richard; Kienast, Thorsten; Hädel, Sven; Heidenreich, Jens Olaf; Schmitz, Stephan; Kunz, Dieter

doi:10.1016/j.sleep.2008.05.003

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Volume 10, Issue 4 , Pages 439-445, April 2009

Degree of pineal calcification (DOC) is associated with polysomnographic sleep measures in primary insomnia patients

Richard Mahlberg
- Department of Physiology, Charité Campus Benjamin Franklin, Charité – Universitätsmedizin Berlin, Arnimallee 22, D-14195 Berlin, Germany
- Institute of Psychogerontology, Naegelsbachstr. 25, D-91052, Erlangen, Germany
- Corresponding author. Address: Institute of Psychogerontology, Naegelsbachstr. 25, D-91052, Erlangen, Germany. Tel.: +49 9131 753 2300; fax: +49 9131 753 2725.
- These authors contributed equally to this paper.
Thorsten Kienast
- Department of Psychiatry and Psychotherapy, Charité Campus Mitte, Charité – Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
- These authors contributed equally to this paper.
Sven Hädel
- Department of Physiology, Charité Campus Benjamin Franklin, Charité – Universitätsmedizin Berlin, Arnimallee 22, D-14195 Berlin, Germany
Jens Olaf Heidenreich
- Department of Radiology, Charité Campus Benjamin Franklin, Charité – Universitätsmedizin Berlin, Hindenburgdamm 30, D-12200 Berlin, Germany
- Department of Radiology, University of Louisville Hospital, University of Louisville, 530 South Jackson Street, Louisville, KY 40202, USA
Stephan Schmitz
- Department of Radiology, Charité Campus Benjamin Franklin, Charité – Universitätsmedizin Berlin, Hindenburgdamm 30, D-12200 Berlin, Germany
Dieter Kunz
- Department of Physiology, Charité Campus Benjamin Franklin, Charité – Universitätsmedizin Berlin, Arnimallee 22, D-14195 Berlin, Germany

Received 7 May 2008; accepted 7 May 2008.

Abstract

Objective

Melatonin plays a key role in the proper functioning of the circadian timing system (CTS), and exogenous melatonin has been shown to be beneficial in cases of CTS and sleep disturbances. Nevertheless, the concept of “melatonin deficit” has yet to be defined. The aim of our study was, therefore, to determine the relationship between the degree of pineal calcification (DOC) and a range of sleep parameters measured objectively using polysomnography (PSG).

Methods

A total of 31 outpatients (17 women, 14 men, mean age 45.9 years; SD 14.4) with primary insomnia were included in our study. Following an adaptation night, a PSG recording night was performed in the sleep laboratory. Urine samples were collected at predefined intervals over a 32-h period that included both PSG nights. The measurement of 6-sulphatoxymelatonin (aMT6s) levels was determined using ELISA. DOC and volume of calcified pineal tissue (CPT) and uncalcified pineal tissue (UPT) were estimated by means of cranial computed tomography.

Results

UPT was positively associated with 24-h aMT6s excretion (r=0.569; P=0.002), but CPT was not. After controlling for age, aMT6s parameters, CPT, and UPT did not correlate with any of the PSG parameters evaluated. In contrast, DOC was negatively associated with REM sleep percentage (r=−0.567, P=0.001), total sleep time (r=−0.463, P=0.010), and sleep efficiency (r=−0.422, P=0.020).

Conclusion

DOC appears to be a superior indicator of melatonin deficit compared to the absolute amount of melatonin in the circulation. High DOC values indicate changes predominantly in the PSG parameters governed by the circadian timing system. DOC may thus serve as a marker of CTS instability.

Keywords: Sleep, Pineal gland, Melatonin, Degree of pineal calcification (DOC), Polysomnography, Rapid eye movements (REM), Age