Addition of test components during neurodynamic testing: Effect on range of motion and sensory responses

Study Design: Single session, repeated-measures design. Objectives: To analyze the impact of different components of the neural tissue provocation test for the median nerve (NTPT1) on the range of motion (ROM) of the elbow and wrist and the sensory responses elicited by the test. Background: The assessment of minor peripheral nerve injuries by neurodynamic tests is becoming more integrated in physical therapy practice. The influence of different test components on the nervous system has been analyzed in numerous in vitro studies, but in vivo studies are still lacking. Methods and Measures: Five test variations were performed on 35 asymptomatic men (23.5 +/- 2.3 years). Elbow extension was performed (1) without additional components (NTPT1(NEUTRAL)), (2) with wrist extension (NTPT1(WE)), (3) with cervical contralateral lateral flexion (NTPT1(CLLF)), and (4) with both wrist extension and cervical contralateral lateral flexion (NTPT1(WE+CLLF)). In the fifth variant, the wrist was extended from a preloaded position (WENTPT1). The range of elbow and wrist extension when a submaximal discomfort was elicited was measured with 2 electrogoniometers. Results: The addition of each test component resulted in a significantly reduced ROM (NTPT1(NEUTRAL): 179.5 +/- 8.8 degrees, NTPT1(WE): 169.0 +/- 13.9 degrees, NTPT1(CLLF): 154.7 +/- 13.2 degrees, NTPT1(WE+CLLF): 143.9 +/- 16.1 degrees; WENTPT1: 67.1 +/- 11.0 degrees). Sensory responses were predominantly evoked at the region of the added component. Conclusions: The different test components, whose mechanical influence on the nervous system has been demonstrated in anatomical studies, also have an effect on joint ROM and sensory responses during neurodynamic testing, when individually or simultaneously added. If the nerve bedding is elongated throughout its whole length, the available ROM is markedly reduced and sensory responses can be elicited throughout the entire arm.