Test-Retest Reliability of Local Tissue Water and Circumference Measurements in the Head and Neck Area of Healthy Women and Men

Background: Measurements of local tissue water and circumferences are methods to evaluate lymphedema. Knowledge about reference values and reproducibility needs, however, to be determined for the head and neck (HN) area of healthy persons before it can be used in persons with HN lymphedema. The objective of this study was to evaluate the test-retest reliability including measurement errors of local tissue water and neck circumference measurements (CM) in the HN area in a healthy cohort.Methods and Results: Thirty-one women and 29 men were measured on 2 occasions, 14 days apart. The percentage of tissue water content (PWC) were calculated in four facial points and neck CM at three levels. Intraclass correlation coefficient (ICC), changes in mean, standard error of measurement (SEM%), and smallest real difference (SRD%) were calculated. Reliability for PWC was fair to excellent for both women (ICC 0.67-0.89) and men (ICC 0.71-0.87). Measurement errors were acceptable in all points in both women (SEM% 3.6%-6.4%, SRD% 9.9%-17.7%) and men (SEM% 5.1%-10.9%, SRD% 14.2%-30.3%). For the CM, ICCs were excellent both for women (ICC 0.85-0.90) and men (ICC 0.92-0.94), and measurement errors were low (SEM% for women 1.9%-2.1%, SRD% 5.1%-5.9%; SEM% for men 1.6%-2.0%, SRD% 4.6%-5.6%). Most of the lowest values were found close to bone and vessels.Conclusion: Measurements for PWC and CM in the HN area are reliable in healthy women and men, with acceptable to low measurement errors. PWC points close to bony structures and vessels should, however, be used with caution.