Pediatric Neurology 50 (2014) 195e196

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Visual Diagnosis

Redefining the “Hyperphotoconvulsive” Response of Late-Infantile Neuronal Ceroid Lipofuscinosis Afsaneh Talai a, Yu-Tze Ng MD b, * a b

University of Oklahoma College of Medicine, Oklahoma City, Oklahoma Department of Neurology, University of Oklahoma, Oklahoma City, Oklahoma

We present a 4-year-old girl with late-infantile neuronal ceroid lipofuscinosis diagnosed by low tripeptidyl peptidase I activity and a corneal biopsy of a biological sister with a similar clinical picture. She had a 2-year history of refractory epilepsy manifested by myoclonic, generalized tonic-clonic, and atypical absence seizures. She developed progressive global developmental delay and regression, losing her ability to walk and talk. On examination, she was nonverbal, had diffuse hypotonia with hyperreflexia with sustained bilateral ankle clonus, and Babinski sign bilaterally. The girl has a biological sister with the same diagnosis. Her sister’s corneal biopsy (Fig 1) revealed curvilinear inclusion material characteristic of late-infantile neuronal ceroid lipofuscinosis.1 Our patient’s electroencephalogram showed mild diffuse slowing and only rare epileptiform discharges. A single 1-second burst of “fast” 4- to 5-Hz irregular generalized spike-and-slow wave discharge and two fragmented right centrotemporal, broad-field spike-and-slow wave discharges were seen. However, during photic stimulation the presence of dramatic photoconvulsive response of 2.5to 3.5-Hz irregular generalized spike-and-slow wave discharges at all tested flash frequencies (1 to 21 Hz, including frequencies of every odd number in between) was present throughout the entire duration of photic stimulation of every single flash frequency used. Figure 2A depicts the start of a photoconvulsive response to a flash frequency of 13 Hz with spike-and-slow wave discharges. Figure 2B depicts the photoconvulsive response to flash frequencies of 15 Hz. In addition as shown in these two electroencephalograms, the occipital leads demonstrate attempts to “drive” or “spike” at the photic simulation frequency!

Y.T. Ng is a paid consultant for Lundbeck, Inc. and is on the speakers’ bureau for UCB Pharma, Lundbeck Inc., Supernus Pharmaceuticals Inc., and Cyberonics Inc. He is an associate editor for Pediatric Neurology.

* Communications should be addressed to: Dr. Ng; Department of Neurology; University of Oklahoma; Health Sciences Center; 711 Stanton L. Young Blvd.; Ste 215; Oklahoma City, OK 73104. E-mail address: [email protected] 0887-8994/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pediatrneurol.2013.09.005

FIGURE 1. Electron microscopic examination of a conjunctival specimen reveals, within the vascular pericytes, large lysosomal inclusions containing curvilinear membranous profiles. This finding is characteristic of lateinfantile neuronal ceroid lipofuscinosis.

During several of the photic simulation episodes, the electroencephalograph technologist documented that the patient had some jerking and/or eye blinking, meaning that some or all of these dramatic photoconvulsive responses may have represented myoclonic-atypical absence seizures. Classically, late-infantile neuronal ceroid lipofuscinosis is characterized by photoconvulsive response only to low flash frequencies of 1-5 Hz; this is not an uncommon teaching point.2 Photosensitivity typically occurs at flash frequencies of 10-30 Hz in photosensitive epilepsies. Low-frequency photoparoxysmal response can also occur in Lafora disease and mitochondrial disease in addition to late-infantile neuronal ceroid lipofuscinosis.3 Prior studies have also shown photoparoxysmal response in response to higher flash frequencies in a small portion of late-infantile neuronal ceroid lipofuscinosis patients.2

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A. Talai, Y.-T. Ng / Pediatric Neurology 50 (2014) 195e196

FIGURE 2. (A) Electroencephalograph at baseline, with start of photic stimulation at 13 Hz with associated photoconvulsive response on a “traditional” 10-second page. (B) Electroencephalograph with start of photic stimulation at 15 Hz with associated photoconvulsive response throughout the entire duration of the photic stimulation on a compressed 20-second page.

Although photosensitivity at low flash frequencies is very specific to late-infantile neuronal ceroid lipofuscinosis and is still a helpful aid in diagnosis, one should realize that the presence of photosensitivity at higher frequencies cannot rule out late-infantile neuronal ceroid lipofuscinosis; indeed, such a dramatic broad photoconvulsive response should prompt the consideration of this devastating diagnosis.

References 1. Puri P, Valdes C, Selim M, et al. Neuronal ceroid lipofuscinosis diagnosed via skin biopsy. J Clin Neurosci. 2010;17:1585-1587. 2. Binelli S, Canafoglia L, Panzica F, et al. Electroencephalographic features in a series of patients with neuronal ceroid lipofuscinoses. Neurol Sci. 2000;21:83-87. 3. Guellerin J, Hamelin S, Sabourdy C, et al. Low-frequency photoparoxysmal response in adults: an early clue to diagnosis. J Clin Neurophysiol. 2012;29:160-164.

Redefining the "hyperphotoconvulsive" response of late-infantile neuronal ceroid lipofuscinosis.

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