Correlation between bioelectrical spectroscopy and perometry in assessment of upper extremity swelling

Lymphedema is a common side effect of breast cancer treatment and is associated with increased upper extremity volume, functional impairment, and pain. While there is no cure for lymphedema, physical therapy treatment can often alleviate symptoms. To measure the efficacy of treatment, accurate assessment of the limbs is important. Current methods of assessment are complex (water displacement), marginally accurate (circumferential measurements), or expensive (opto-electrical systems). A new method for estimating tissue fluid is bioelectrical spectroscopy (BIS). This method measures impedance to small currents applied to the body and is easily performed. Acceptance of BIS devices for assessment of limb fluid will be dependent on the establishment of sufficient reliability and validity, and the objective of this study was to evaluate reliability and validity of this device compared to perometry. Both upper limbs of ten subjects previously treated for breast cancer were measured using BIS and perometry. We found that inter-rater reliability (r = 0.987) and intrarater reliability (r = 0.993) were acceptably high for the BIS unit and concurrent validity was r = -0.904, when compared to perometry. These results confirm that BIS can produce valid and reliable data related to the assessment of upper limbs affected by lymphedema.