Participants in this group will receive the sham treatment first, then the experimental treatment.

Participants in this group will receive the experimental treatment first, then the sham treatment.

This phototherapy device (PTD-1) consists of a Plexiglas hand compartment (cleanable) enclosed in a powder-coated steel cabinet. Within the cabinet are two blue LED panels located above and below the hand compartment to illuminate the hands.

Participants will be asked to rate their pain upon cold room exposure between treatments using a 10 centimeter visual analog scale (VAS). Outcome is reported as the mean change in VAS per arm in units of millimeters.

Participants will be asked to rate their numbness upon cold room exposure between treatments using a 10 centimeter visual analog scale (VAS). Outcome is reported as the mean change in VAS per arm in units of millimeters.

Skin temperature of at least one finger will be measured and logged using a thermometer at multiple points during study visit. Outcome is reported in units of degrees Celsius.

The thermal imaging camera takes still images of the hand before and immediately after treatment. It provides a heat map (color contour) that may be probed afterwards for temperature at designated points. These points are distributed over the fingers, hand and palms. A technician manually reads the temperature in degrees Celsius and enters the values into an Excel spreadsheet designating subject, ID and date; location of measurement; and other temperature readings. These include ambient (room temperature), and outside temperature. The finger and room temperatures, in Celsius, are electronically recorded on an Omega data logger. This is interrogated later to retrieve data. Another continuous reading is obtained of the temperature inside the hand compartment (separate from internal thermoregulation measurements) to track equipment functionality.