TGI Friday! Our regular round-up of research abstracts, 2 March 2012

March 2, 2012

Our weekly round-up of research abstracts that have not already appeared on this website.

Sleep. 2011 Nov 1;34(11):1551-60.

Sleep-stage dynamics in patients with chronic fatigue syndrome with or without fibromyalgia.

Kishi A, Natelson BH, Togo F, Struzik ZR, Rapoport DM, Yamamoto Y.
Educational Physiology Laboratory, Graduate School of Education, University of Tokyo, Tokyo, Japan.


STUDY OBJECTIVES: Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are medically unexplained conditions that often have overlapping symptoms, including sleep-related complaints. However, differences between the 2 conditions have been reported, and we hypothesized that dynamic aspects of sleep would be different in the 2 groups of patients.

PARTICIPANTS: Subjects were 26 healthy control subjects, 14 patients with CFS but without FM (CFS alone), and 12 patients with CFS and FM (CFS+FM)-all women.

MEASUREMENTS AND RESULTS: We studied transition probabilities and rates between sleep stages (waking, rapid eye movement [REM] sleep, stage 1 [S1], stage 2 [S2], and slow-wave sleep [SWS]) and duration distributions of each sleep stage. We found that the probability of transition from REM sleep to waking was significantly greater in subjects with CFS alone than in control subjects, which may be the specific sleep problem for people with CFS alone. Probabilities of (a) transitions from waking, REM sleep, and S1 to S2 and (b) those from SWS to waking and S1 were significantly greater in subjects with CFS+FM than in control subjects; in addition, rates of these transitions were also significantly increased in subjects with CFS+FM. Result (a) might indicate increased sleep pressure in subjects with CFS+FM whereas result (b) may be the specific sleep problem of subjects with CFS+FM. We also found that shorter durations of S2 sleep are specific to patients with CFS+FM, not to CFS alone.

CONCLUSIONS: These results suggest that CFS and FM may be different illnesses associated with different problems of sleep regulation.

PMCID: PMC3198210 [Available on 2012/5/1]
PMID: 22043126 [PubMed – indexed for MEDLINE]

In Vivo. 2011 Nov-Dec;25(6):1019-25.

Serotonergic descending inhibition in chronic pain: design, preliminary results and early cessation of a randomized controlled trial.

Meeus M, Ickmans K, De Clerck LS, Moorkens G, Hans G, Grosemans S, Nijs J.
Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Building L-Mfys, Pleinlaan 2, 1050 Brussels, Belgium.


AIM: We examined whether activation of serotonergic descending pathways improves pain inhibition during exercise in patients with chronic fatigue syndrome (CFS) and comorbid fibromyalgia (FM) in comparison with rheumatoid arthritis (RA) and sedentary, healthy controls in a double-blind randomized controlled trial with cross-over design.

PATIENTS AND METHODS: Three female CFS/FM patients, one female RA patient and two healthy women were randomly allocated to the experimental group (2 ml of citalopram intravenously) or the placebo group (2 ml of 0.9% NaCl intravenously). Participants performed a submaximal exercise protocol, preceded and followed by an assessment of endogenous pain inhibition. Seven days later, groups were crossed over.

RESULTS: Significant side-effects were observed in all, but one participant immediately after intravenous administration of citalopram. One CFS/FM patient withdrew because of severe post-exertional malaise.

CONCLUSION: It was decided that proceeding with the study would be unethical. No conclusion could be made regarding pain inhibition during exercise in CFS/FM compared to RA and controls.

PMID: 22021700 [PubMed – indexed for MEDLINE]

Arch Oral Biol. 2011 Oct;56(10):1142-7. Epub 2011 May 25.

Xerostomia and salivary flow in patients with orofacial pain compared with controls.

da Silva LA, Teixeira MJ, de Siqueira JT, de Siqueira SR.
Neurology Department, Medical School, University of Sao Paulo, Sao Paulo, Brazil.


OBJECTIVES: Pain in the orofacial region is frequently reported by patients in dental and medical offices. Facial pain, headache, masticatory abnormalities and other complaints often become chronic and may be associated with local disturbances, such as xerostomia and teeth abnormalities. The objective of this study was to investigate salivary flow and xerostomia in patients with orofacial pain.

DESIGN: This was a case-control study; we evaluated 82 patients with chronic orofacial pain compared with 56 healthy subjects using a Clinical Pain Questionnaire (pain characteristics, duration, intensity and descriptors), complete dental examination (including static and dynamic evaluation of the jaw) and a Xerostomia Inventory. The salivary flow was quantitatively evaluated. Data was compared through Pearson's chi-square, Fisher's exact, analysis of variance (ANOVA) 1 factor and Mann-Whitney tests.

RESULTS: Patients often had temporomandibular disorder (TMD) (P=0.001) and pain during facial (P<0.001) and neck palpation (P=0.002). There were no differences in dental examination or other structural aspects of the jaw between the groups. There were more complaints associated with xerostomia in the study group, including burning sensation in the oral mucosa (P=0.003), in the throat (P=0.035) and in the stomach (P=0.050). Patients had lower salivary flow (P=0.008).CONCLUSIONS: Orofacial pain patients need to be evaluated with regard to their salivary function, which was often found abnormal in this sample and may have contributed to the complaints of these patients. Assessing salivary flow and xerostomia may help in the treatment of chronic orofacial pain.Copyright © 2011 Elsevier Ltd. All rights reserved. PMID: 21612767 [PubMed - indexed for MEDLINE]

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