REM sleep augmentation with extra-ocular light

Abstract

The invention provides for exposing an extraocular (i.e., non-ocular) region of a human to light during sleep, which enhances REM sleep. Also provided are devices to carry out the methods. Key timing parameters ensure effective REM enhancement without adversely impacting a subject's circadian clock. The invention provides for improving cognitive function and performance in healthy individuals and in individuals suffering from a disease or disorder in which mental status is compromised.

What is claimed is:  
     
         1 . A method for enhancing REM sleep in a subject, which method comprises exposing a non-ocular region of a subject to photic stimulation for an interval during a sleep period.  
     
     
         2 . The method according to  claim 1 , wherein enhancing REM sleep comprises increasing the number of minutes spent in REM sleep during the interval of photic stimulation.  
     
     
         3 . The method according to  claim 2 , wherein the number of minutes in REM sleep increases by at least about 30%.  
     
     
         4 . The method according to  claim 2 , wherein the number of minutes in REM sleep increases by at most about 200%.  
     
     
         5 . The method according to  claim 1 , wherein enhancing REM sleep comprises increasing the frequency of REM periods during the interval of photic stimulation.  
     
     
         6 . The method according to  claim 5 , wherein the frequency of REM periods increases by about 40%.  
     
     
         7 . The method according to  claim 1 , wherein the non-ocular region is a region of ample surface vasculature.  
     
     
         8 . The method according to  claim 7 , wherein the region of ample surface vasculature is the popliteal fossa.  
     
     
         9 . The method according to  claim 1 , wherein the interval lasts for a duration ranging from between about 15 minutes to about 12 hours.  
     
     
         10 . The method according to  claim 9 , wherein the duration is about three hours.  
     
     
         11 . The method according to  claim 1 , wherein the photic stimulation has an intensity ranging from about 15 lux to about 150,000 lux.  
     
     
         12 . The method according to  claim 11 , wherein the photic stimulation has an intensity ranging from about 10,000 lux to about 13,000 lux.  
     
     
         13 . The method according to  claim 1 , wherein the photic stimulation has a bandwidth in the visible spectrum.  
     
     
         14 . The method according to  claim 13 , wherein the photic stimulation has a bandwidth between about 455 nanometers (nm) and 540 nm.  
     
     
         15 . The method of  claim 1 , which method further comprises enhancing cognitive function in a subject.  
     
     
         16 . The method according to  claim 15 , wherein the subject suffers from a medical disorder in which mental status is compromised.  
     
     
         17 . The method according to  claim 15 , wherein the subject is a normal individual.  
     
     
         18 . The method according to  claim 15 , wherein cognitive function is enhanced to a degree comparable to that achieved with a cholinergic agonist.  
     
     
         19 . A method for extending a REM cycle of a person, comprising the steps of: 
 a) sensing the start of the REM cycle;    b) sensing the end of the REM cycle;    c) determining the time interval of the REM cycle; and    d) augmenting the time interval of the REM cycle by selectively providing non-ocular photic stimulation for a predetermined interval.    
     
     
         20 . An article for extending a REM cycle of a person, comprising: 
 a) a sensor which provides phasic activity signals;    b) a timing circuit connected to the sensor and outputting an elapsed-interval signal indicative of the magnitude of the REM cycle;    c) a comparator which compares the elapsed-interval signal to a predetermined-interval signal and outputs a shortfall signal;    d) a controller responsive to the shortfall signal to generate a control signal;    e) a photic stimulator positionable in contact with the person's skin and being actuated in response to the control signal.    
     
     
         21 . The article as in  claim 20 , wherein the controller further generates an update signal which is provided to the comparator as the predetermined-interval signal during a subsequent REM cycle.