451 JRRD JRRD Volume 49, Number 3, 2012 Pages 451–458 Single session of brief electrical stimulation immediately following crush injury enhances functional recovery of rat facial nerve Eileen M. Foecking, PhD; 1–2* Keith N. Fargo, PhD; 2–3 Lisa M. Coughlin, MD; 2 James T. Kim, MD; 4 Sam J. Marzo, MD; 1 Kathryn J. Jones, PhD 1–2,5 1 Department of Otolaryngology–Head and Neck Surgery, Stritch School of Medicine, Loyola University Chicago, Maywood, IL; 2 Research & Development Service, Edward Hines Jr Department of Veterans Affairs Hospital, Hines, IL; 3 Department of Molecular Pharmacology and Therapeutics, 4 Neuroscience Program, and 5 Department of Microbi- ology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL Abstract—Peripheral nerve injuries lead to a variety of patho- logical conditions, including paresis or paralysis when the injury involves motor axons. We have been studying ways to enhance the regeneration of peripheral nerves using daily electrical stimu- lation (ES) following a facial nerve crush injury. In our previous studies, ES was not initiated until 24 h after injury. The current experiment tested whether ES administered immediately follow- ing the crush injury would further decrease the time for complete recovery from facial paralysis. Rats received a unilateral facial nerve crush injury and an electrode was positioned on the nerve proximal to the crush site. Animals received daily 30 min sessions of ES for 1 d (day of injury only), 2 d, 4 d, 7 d, or daily until com- plete functional recovery. Untreated animals received no ES. Ani- mals were observed daily for the return of facial function. Our findings demonstrated that one session of ES was as effective as daily stimulation at enhancing the recovery of most functional parameters. Therefore, the use of a single 30 min session of ES as a possible treatment strategy should be studied in human patients with paralysis as a result of acute nerve injuries. Key words: electrical stimulation, facial nerve, facial paraly- sis, functional recovery, injury, motoneuron, peripheral nerve, regeneration, repair, therapy. INTRODUCTION Peripheral nerve damage can lead to serious sensory and/or motor dysfunctions. The facial nerve is the most commonly injured cranial nerve. Injury to the facial nerve can have many causes, the most prevalent being Bell palsy, compression or stretching of the nerve caused by tumors or bone fractures, and transection. The facial nerve’s suscep- tibility to injury arises from its complex anatomical course from the brain stem to its target muscles. The severity of facial paresis and the recovery outcome depend on the site of facial nerve injury, with the greater damage observed with an injury more proximal to the cell bodies. Although peripheral nerves are remarkable for their regenerative capacity, recovery from nerve damage can be slow and/or incomplete. Therefore, understanding the factors that can enhance the regenerative process following peripheral nerve damage is important so that therapies can be devel- oped to target such factors. Applying electrical stimulation (ES) has been shown to affect morphological and functional properties of neu- rons such as nerve branching, rate and orientation of neurite growth, rapid sprouting, and guidance during axon regeneration [1–4]. Therefore, ES has been explored Abbreviations: ANOVA = analysis of variance, ES = electrical stimulation. * Address all correspondence to Eileen M. Foecking, PhD; Edward Hines Jr VA Hospital, Research & Development Service, 5000 S. 1st Ave, Building 1, Rm A241, Mail 151, Hines, IL 60141; 708-202-5818; fax: 708-202-2327. Email: Eileen.Foecking@va.gov http://dx.doi.org/10.1682/JRRD.2011.03.0033