The frequent negativity of neuroradiological changes after neck injury despite the constant complaints (neck pain and stiffness, limited neck movements, arm pains) experienced after a motor vehicle crash has led us to verify the diagnostic and prognostic validity of different neurophysiological tests in these patients. To this aim 120 young patients (67 females and 53 males) referred for a whiplash syndrome aged 18-31 years without neuroradiological abnormalities have been submitted to EMG and BAEP studies immediately after the traffic accident and after six months. Constant slowing of median MNCV and SNCV and ulnar SNCV without changes in morphology, amplitude and duration of MAP and SAP have been observed in 92 patients, with persistent abnormalities in 64 cases after six months. Increase in I-III or I-V interpeak interval of BAEP have been observed unilaterally in 45 patients and bilaterally in 32 ones without changes in absolute latencies and V/I amplitude ratio, with persistence of such abnormalities in 31 and 16 patients respectively after six months. Simultaneous abnormalities of all neurophysiological tests have been observed in 31 patients, with unmodified recordings after six months in 24 patients. The above findings could be accounted for subtle cerebral lesions and a possible damage to brain stem structures as claimed by Ettlin et al. (1992). The usefulness of the above proposed neurophysiological tests in assessment of asymptomatic dysfunction of central motor and sensory pathways in whiplash injuries is discussed.