When pain adversely affects a patient's activities its diagnosis needs to be fast and accurate to allow effective treatment to be commenced as soon as possible. Difficulties may be found in achieving this, however, in elderly patients with age-associated cognitive decline, as they may not be capable of properly understanding or recalling their symptoms. The present case concerns a 77-year-old woman who presented with the chief complaint of pain in the right mandible persisting throughout the day, and severe enough to necessitate her lying down in bed all day long. The use of open-ended questions followed by a structured interview focused on pain with closed-ended questions revealed that she experienced paroxysms of pain throughout the day and that she was afraid of its occurrence. Based on these findings, the diagnosis was trigeminal neuralgia. Carbamazepine decreased the pain with no side effects. The patient continued taking carbamazepine for 3 months, during which time she was closely monitored for adverse reactions. No side effects, such as drowsiness or dizziness, were observed, however, and the pain subsided completely with no recurrence, even after cessation of carbamazepine.