Neurofibromatosis type 1 (NF1) is a common, autosomal dominant neurocutaneous disorder in which any organ system, including the skin, skeleton and nervous system can be affected. In this study, we compared the electrophysiological and magnetic resonance imaging (MRI) findings in patients with NF1. Thirty-nine adolescent and adult patients (23 women and 16 men) diagnosed with NF1 with a mean age of 25.8 +/- 10 years (10-56) were included in this study. We collected data in the form of the results of neurological examinations, multimodal evoked potentials (EPs; brainstem auditory evoked potentials. BAEPs; somatosensory evoked potentials. SEPs; and visual evoked potentials, VEPs), cerebral/orbital/spinal MRIs, and electroneuromyography (ENMG). Twenty (513%) patients showed abnormal VEPs, 14(35.9%) showed abnormal SEPs, and six (15.4%) showed abnormal BAEPs. All evoked potentials were abnormal in four (10.3%) cases. These electrophysiological findings occurred primarily in the absence of any clinical sign related to the affected system. MRI revealed pathologic findings in 26 of 39 patients, and these were not always correlated with visual, auditory, or somatosensory pathway abnormalities. ENMG showed polyneuropathy in two of 33 patients who underwent ENMG. Our study showed that MRI and electrophysiological abnormalities may be found in most patients with NF1, even in the absence of associated clinical symptoms or signs. Electrophysiological testing is helpful for monitoring the subclinical involvement of the central and peripheral nervous systems in patients with NF1. (C) 2011 Elsevier B.V. All rights reserved.