Abstract
During our practice of clinical neurological examination we frequently observed that patients, upon testing of cranial nerve VII, when instructed to "wrinkle their forehead" (to evaluate the innervation of the M. frontalis), seem to falsely "frown" (i.e. innervate the corrugator supercilii). Here, we set out to prospectively evaluate prevalence and characteristics of this phenomenon. Using a semi-structured questionnaire, we show that the majority of colleagues at our center shared our observation. Further, we demonstrate that of 113 unselected prospectively examined patients in fact 54.9% showed false frowning. This effect was irrespective of gender and only marginally influenced by age, chief complaint and clinical setting. Of note, all patients with initial frowning (or other "incorrect" reaction), when instructed to "raise their eye-brows", showed correct wrinkling. In summary, we were able to prospectively assess a highly prevalent artifact of the clinical exam, highlighting the critical significance of the correct wording during the neurological exam.