Memantine treatment for neuropsychiatric symptoms in a patient with probable idiopathic normal pressure hydrocephalus: a case report

INTRODUCTION: Patients with idiopathic normal pressure hydrocephalus often show neuropsychiatric symptoms besides the triad of ‘classic’ symptoms. Memantine has been reported to have positive effects on the neuropsychiatric symptoms of patients with Alzheimer’s disease and patients with dementia with Lewy bodies. We administered memantine to a Japanese patient with probable idiopathic normal pressure hydrocephalus, hoping that this treatment would have positive effects on the neuropsychiatric symptoms of his idiopathic normal pressure hydrocephalus. CASE PRESENTATION: An 80-year-old right-handed Japanese man was diagnosed as having probable idiopathic normal pressure hydrocephalus and showed neuropsychiatric symptoms as well as the triad of classic symptoms of idiopathic normal pressure hydrocephalus. We treated our patient with memantine by increasing, decreasing, and then again increasing the dose of memantine. We evaluated his neuropsychiatric symptoms using the Neuropsychiatric Inventory at baseline, after the dose was increased to 20mg/day, after the dose was decreased to 5mg/day, and after the dose was increased again to 15mg/day. We simultaneously evaluated the triad of symptoms and conducted neuropsychological tests. In addition, we evaluated the psychological distress of our patient’s caregiver using the Zarit Caregiver Burden Interview. CONCLUSIONS: Memantine had positive effects on the neuropsychiatric symptoms of our patient with idiopathic normal pressure hydrocephalus. Although none of his triad of classic symptoms, including cognitive abilities, improved, the psychological distress of our patient’s caregiver improved.