Classifying Whiplash Recovery Status Using the Neck Disability Index: Optimized Cutoff Points Derived From Receiver Operating Characteristic.

Objective: Researchers often use Neck Disability Index (NDI) scores to classify recovery status in whiplash patients. The purpose of this study was to investigate the optimal cutoff point score for the NDI as a mechanism for differentiating recovery from nonrecovery after whiplash.

Methods: Subjects (N = 123) who had previously sustained whiplash injuries were recruited from 12 clinics.