A hemispherotomy for intractable startle epilepsy characterized by infantile hemiplegia and drop attacks Mitsuhiro Anan a, * , Tohru Kamida a , Eiji Abe a , Takeshi Kubo a , Tatsuya Abe a , Takamitsu Hikawa a , Minoru Fujiki a , Hidenori Kobayashi a , Hiroshi Baba b a Department of Neurosurgery, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Yufu, Oita 879-5593, Japan b Department of Neurosurgery, National Nagasaki Medical Center, Omura, Nagasaki, Japan article info Article history: Received 23 January 2009 Accepted 11 March 2009 Keywords: Drop attacks Hemispherotomy Startle epilepsy Surgical treatment abstract Startle epilepsy is provoked by unexpected sensory stimuli, mainly auditory, and reveals subsequent tonic posturing of the limbs. We present a case of intractable startle epilepsy with infantile hemiplegia and discuss the indications for a hemispherotomy. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Startle epilepsy is characterized by seizures provoked by sud- den and unexpected sensory stimuli, mainly auditory. Startle- provoked tonic posturing of the limbs causes drop attacks that threaten the patients’ lives. The seizures are refractory to medical treatments. Surgical treatment should thus be considered an option for controlling seizures, but there are very few surgical reports on this topic. We discuss the indications for a hemispherotomy to treat intractable startle epilepsy with infan- tile hemiplegia and drop attacks. 2. Case report An 11-year-old boy, who suffered a severe head injury at the age of 10 months and underwent surgical treatment, was admit- ted to our department. He had had medically intractable seizures for the 4 years prior to presentation. He had reflex seizures and began taking antiepileptic drugs at the age of 7 years, but the sei- zures continued to get worse with a frequency of several times per day by the age of 10 years. The seizures were provoked by sudden unexpected events, mainly loud sounds, but also some- times when he was touched from behind. They were character- ized by the extension of the right upper limb followed by falling to the rear, continuously laughing, and a brief loss of con- sciousness lasting seconds to minutes. If he was standing at the time of a seizure, he dropped to the floor and was frequently injured. A neuropsychological and neurological examination on admis- sion showed an IQ of 52 on the Tanaka-Binet intelligence scale and right hemiplegia. He was able to elevate the right upper limb to shoulder height, but without any useful finger function. He was also able to walk by himself without flexion of the ankle. His speech function was unaffected and Wada testing indicated lan- guage function in the right cerebral hemisphere. The MRI demonstrated left hemispheric atrophy (Fig. 1). Interic- tal 99 m-technetium ethylcysteinate dimer (ECD) single photon emission computed tomography (SPECT) showed hypoperfusion in the left hemisphere and ictal SPECT showed left dorsolateral frontal hyperperfusion. Interictal scalp electroencephalography (EEG) showed sporadic spike waves in the left fronto-temporal or central region (Fig. 2). Ictal scalp video-EEG showed a relative flat- tening of background rhythms with diffuse high frequency activi- ties (Fig. 3). He underwent a left transopercular hemispherotomy (Fig. 4). The histological examination showed few neuronal cells with a marked reactive astrogliosis. After the operation, his right hemiple- gia was transiently aggravated, but it recovered within 3 weeks. He has been seizure-free since the surgery and the neuropsychological and neurological evaluations have revealed no new post-operative deficits for the past 18 months. 3. Discussion We performed a hemispherotomy on a patient suffering from intractable startle epilepsy with infantile hemiplegia. With this ap- proach we obtained successful results. Startle epilepsy has been described as being triggered by mainly unexpected auditory stimuli or sometimes somatosensory or vi- sual stimuli. 1–5 Startle epilepsy typically exhibits uni-/bilateral to- nic posturing of the limbs occasionally leading to drop attacks. 2,3,5 Most patients partially preserve their consciousness 2 and other ic- tal patterns include absences, atonic seizures, generalized seizures, or laughter after absences. 1,2 Previous studies have documented that most patients with star- tle epilepsy have mental retardation, hemiplegia, or tetraparesis and uni-/bilateral hemispheric lesions due to congenital or infan- tile brain damage. 1–6 The patients do not always exhibit neurolog- ical deficits or abnormal neuroimaging. 1 The pathophysiology of startle epilepsy is yet to be ex- plained. The lesions responsible for startle epilepsy vary in the literature. Oguni et al. 3 and Chauvel et al. 7 reported that large epileptogenic lesions involving the primary sensorimotor, premotor, and supplementary motor areas were responsible for the attacks. Other studies have shown that the lateral pre- motor and perisylvian areas 1 or the dorsolateral frontal and supplementary sensorimotor areas 3 play an important role in this phenomenon. Such epileptogenesis may be triggered by * Corresponding author. Tel.: +81 97 586 5862; fax: +81 89 586 5869. E-mail address: annmitsu@med.oita-u.ac.jp (M. Anan) 1652 Case Reports / Journal of Clinical Neuroscience 16 (2009) 1652–1655