Use of a forced-choice test of tactile discrimination in the evaluation of functional sensory loss: a report of 3 cases.

Abstract

The loss of sensation is not an uncommon associated finding after injury to the peripheral nerves and the spinal cord. However, the sensory examination is prone to the influence of nonphysiologic factors, and one cannot use it to determine whether functional sensory loss reflects unconscious or intentional symptom production. This distinction has important implications for differential diagnosis and for decision making in the context of workers' compensation claims and personal injury litigation. We present 3 cases of patients with chronic pain and nondermatomal patterns of loss of fine-touch sensation, whose sensory loss was examined by a sensory forced-choice symptom validity test. Their below-chance scores showed intentionally produced sensory symptoms. The use of this methodology in differential diagnosis is discussed.