10
AASMMembershipSectionsNewsletter
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Issue #5
AmericanAcademy
of SleepMedicine
Top 10CircadianPapersof 2013
TheCircadianRhythms SectionSteeringCommittee combed the literature to identify themost compelling circadianpapers of 2013. The
synopses belowdescribe cutting-edge science and thepotential implicationof these excitingfindings.
Clinical Trials
A randomized controlled trialwithbright light and
melatonin for the treatment of delayed sleepphase
disorder: effects on subjectiveandobjective sleepiness
and cognitive function.
Wilhelmsen-Langeland,A., Saxvig, I.W., Pallesen, S.,Nordhus,
I.H.,Vedaa,O., Lundervold,A. J.,Bjorvatn,B. (2013). JBiol
Rhythms, 28(5), 306-321.
This study investigated the short- and long-term effects of bright
light andmelatonin treatment (in conjunctionwithgradually
advancing rise times) on subjective/objective sleepiness and
cognitive function among adolescents/young adultswithdelayed
sleepphasedisorder (DSPD). Despite the fact thatDSPD is
most commonduring this ageperiod, there are few studies that
are comprisedof suchparticipants. All treatment conditions
investigatedwere essentially equally effective in improvingmost
studiedoutcomes, although long-term treatmentwith light/
melatonin increased someof thepositive effects seen after two
weeks. Despite the various limitations (andmany strengths)
associatedwith the study, it represents apositive step towards
productionof data that canbe readily incorporated into the clinical
environment. (RRA)
Etiology, Mechanisms, andConsequencesof
CircadianRhythmSleep-WakeDisorders
Non-24-HourDisorder inBlind IndividualsRevisited:
Variabilityand the Influenceof EnvironmentalTime
Cues.
Emens, J. S., Laurie,A. L., Songer, J.B.,&Lewy,A. J. (2013).
SLEEP, 36(7), 1091-1100.
Inagroupof patientswithnon-24hourdisorder, circadianphase
(asmeasuredbymelatoninonset)was found todrift inavariable
patternwith significancewithinandbetween subjectdifferences. The
rateof driftofmelatoninonsetwas slowestwhenmelatoninonset
was2000 to0800and fastestwhenmelatoninonsetwas0800 to2000.
Some subjectsdemonstrated longdurationswithnodriftat all. These
findingshighlight theabilityofnon-photiczeitgebers tomodulate
circadianphase inavariable fashion, demonstrate theprincipleof
relativecoordination, and show that individualswithnon-24hour
disordermaybecome transientlyentrained. (CG)
The endogenous circadian temperatureperiod length
(tau) indelayed sleepphasedisorder compared togood
sleepers.
Micic,G., deBruyn,A., Lovato,N.,Wright,H.,Gradisar,M.,
Ferguson, S., et al. (2013). JSleepRes, 22(6), 617-624.
This is thefirst case series todescribe an abnormally long tau as a
potentialmechanismbehinddelayed sleepphasedisorder (DSPD).
Thefindings provide apotential explanation for difficulties that such
patients havewithphase advancing to amore conventional sleep
time (and alsomay explain frequent relapse following treatment).
Theoutcome should spur further chronobiological/behavioral
research and related clinical treatment applications. (RRA)
The impact of circadianmisalignment onathletic
performance inprofessional football players.
Smith,R. S., Efron,B.,Mah,C.D.,&Malhotra,A. (2013). SLEEP,
36(12), 1999-2000.
Whenwest coast football teams play east coast teams they
maybe at a circadian advantageduring eveninggames. As
physical performancepeaks in the late afternoon andwest coast
teams operate at an endogenous time 3hours earlier than their
competitors, they are closer to the circadianpeakof performance
whenplaying an8PM start time gameon the east coast. This
hypothesiswas testedby a40year reviewof all games playedon the
east coastmatching awest coast teamwith thehome team. West
coast teams beat thepoint spread in70 eveninggames as compared
to east coast teams,whobeat thepoint spread inonly36 evening
games. Nodifferencewas foundwhengameswereplayedduring
thedaywhich supports thehypothesis that circadian timingof
performance contributes to the superior showingbywest coast
teams. (CG)
BasicHumanResearch
Eveningambient light exposure can reduce circadian
phaseadvances tomorning light independent of sleep
deprivation.
Burgess,H. J. (2013). JSleepRes, 22(1), 83-88.
Previous studies have found that short sleep episodes reduce
phase advances; however, themechanisms of these reductions
