1: Chronobiol Int. 2007;24(3):521-37.

Primary and secondary features of Parkinson's disease improve with strategic
exposure to bright light: a case series study.

Willis GL, Turner EJ.

The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre,
Kyneton, Victoria, Australia. gwillbro@nex.net.au

The antagonism of melatonin in models of Parkinson's disease (PD) can reduce the
severity of motor impairment associated with dopamine (DA) degeneration. In
consideration of the potent antidepressant effects of bright light therapy (LT),
that LT suppresses melatonin secretion, that depression is commonly observed in
PD, and that exposure to constant light facilitates recovery from experimental
PD, the object of the present study was to strategically administer LT to PD
patients and observe the effects on depression, insomnia, and motor performance.
Twelve patients diagnosed with PD were exposed to white fluorescent light for
1-1.5 h at an intensity of 1000 to 1500 lux once daily commencing 1 h prior to
the usual time of sleep onset, approximately 22:00 h in most patients. All
patients were assessed before LT commenced and at two weeks, five weeks, and
regular intervals thereafter. Within two weeks after commencing LT, marked
improvement in bradykinaesia and rigidity was observed in most patients. Tremor
was not affected by LT treatment; however, agitation, dyskinaesia, and
psychiatric side effects were reduced, as verified by decreased requirement for
DA replacement therapy. Elevated mood, improved sleep, decreased seborrhea,
reduced impotence, and increased appetite were observed after LT. LT permitted
the reduction of the dose of L-dopa, bromocriptine, or deprenyl in some patients
by up to 50% without loss of symptom control. Factors limiting the efficacy of LT
included multiple disease states, treatment compliance, polypharmacy, emotional
stress, advanced age, and predominance of positive symptoms. The results of this
case series study confirms previous work describing light as efficacious in the
treatment of PD and suggest that controlled trials may help to elucidate how LT
might be used strategically as an adjunct therapy to improve the morbidity of PD
patients.


PMID: 17612949 [PubMed - indexed for MEDLINE]