Cederwall et al (2006) evaluated a physiotherapeutic treatment intervention in Bell's palsy. A consecutive series of 9 patients with Bell's palsy participated in the study. Participants were enrolled 4 to 21 weeks after the onset of facial paralysis. The study had a single subject experimental design with a baseline period of 2 to 6 weeks and a treatment period of 26 to 42 weeks. Subjects were evaluated using a facial grading score, a paresis index and a written questionnaire created for this study. Every patient was taught to perform an exercise program twice-daily, including movements of the muscles surrounding the mouth, nose, eyes and forehead. All patients improved in terms of symmetry at rest, movement and function. The authors concluded that patients with remaining symptoms of Bell's palsy appear to experience positive effects from a specific training program. Moreover, these investigators noted that a larger study is needed to fully evaluate the treatment.