Self‐Induced Pattern‐Sensitive Epilepsy

Abstract

Case Report: A 6‐year‐old girl developed self‐induced pattern‐sensitive epilepsy. Her elder sister is normal, and there is no family history of epilepsy. She was born after a 39–week gestation at a birth weight of 3,120 g. Her early psychomotor development was normal. She spoke her first meaningful words at 12 months and walked along at 18 months. At 6 years, she developed repetitive myoclonic jerks of the shoulder and arms, mainly on voluntary viewing of vertically striped patterns such as her mother's clothes, gates, and escalator steps. Neither spontaneous nor photosensitive seizures occurred. At 7 years, she first experienced a generalized tonic‐clonic seizure after seeing the mesh of a screen window. Physical and neurologic examinations were unremarkable. The interictal EEGs showed diffuse polyspike‐and‐wave complexes but no photosensitivity, and computed tomography on the head revealed no abnormalities. She was treated with valproate (VPA), which partially suppressed her seizures. After age 10 years, the seizures increased in frequency and occurred exclusively by self‐induction. She displayed an irresistible urge to approach the mesh of screen windows at home every morning and developed myoclonic jerks after staring at the pattern. Even when her parents scolded her not to approach the window and drew a curtain over it, she deliberately opened the curtain and glanced at the mesh, inducing the jerks. She did not seem to relieve any tension through having the seizures. At that age, EEGs showed an ictal generalized polyspike‐and‐wave complex with myoclonic jerks a few seconds after viewing the same mesh pattern as that from her house. Interictal recordings had normal background activities. The EEGs after viewing other patterns were not obtained. Visual evoked responses to flashes were normal. At age 11 years, she developed another generalized tonic‐clonic seizure after viewing a vertically striped pattern in a gate. After an increasing in the dose of VPA, her self‐induced seizures were controlled by the end of her 12th year. However, she had an obsessive interest in patterns until age 12 years. She demanded to view the vertical strips of a notebook, even if her mother prohibited viewing it and concealed the notebook. She did not have other behavioral problems, but her intelligence quotient was 71 on the Kyoto Scale of Psychological Development. Her visual memory was especially poor in the test. She is now 13 years old and still taking VPA. She is seizure free and shows no more obsessive behavior toward patterns. Conclusions: In this patient, only pattern‐sensitive seizures occurred, and only self‐induced seizures after age 10 years. The seizures were primarily myoclonic with rare generalized tonic‐clonic seizures. She also displayed obsessive behavior toward patterns. She did not have photosensitive seizures, and her EEGs showed no photosensitivity. This is not in accordance with the previous reports on the close relation between pattern‐sensitive and photosensitive epilepsy. Her low intelligence quotient was mostly caused by her poor visual memory. This suggests that pattern‐sensitive epilepsy is linked to focal dysfunction involving the occipital lobe.