The authors respond to the two-part article by Ensalada in the November/December 1997 and January/February 1998 issues of The Guides Newsletter. Disability determination in the AMA Guides to the Evaluation of Permanent Impairment often is based on formulations that use a scaled ranking of the impaired function(s) that approximates the impact on the individual's ability to perform specific tasks. The method, although imperfect, generates a percentage impairment score for rating the disability. This method breaks down when applied to disorders with far-reaching effects, such as reflex sympathetic dystrophy (RSD), because it tends to focus only on the affected extremity. The AMA Guides also identifies five factors can affect disability in individuals with RSD: First, RSD spreads in an unpredictable temporal manner. Second, RSD is associated with global effects on cognitive processes (eg, constant pain leads to impairment of sleep, decreased alertness, and altered attention). Third, depression often is a reactive consequence to impaired function. Fourth, RSD may change over time yet may remain quite disabling. Fifth, RSD can significantly affect remote systems (eg, bladder disturbance). For these reasons, during the evaluation of people affected by RSD, physicians should be aware of additional issues besides the percentage loss of function of the affected injured extremity.