The spectrum of epileptic syndromes with fixation off sensitivity persisting in adult life

Abstract

PurposeThe term fixation off sensitivity (FOS) was proposed by Panayiotopoulos to describe epilepsy/electroencephalography (EEG) changes evoked by the suppression of central vision and fixation. The EEG pattern usually consists of spike/polyspike and waves localized in occipital regions. FOS occurs mainly in children with idiopathic occipital partial epilepsies and rarely in adults. In this retrospective study we evaluated the clinical data, EEG, and magnetic resonance imaging (MRI) findings of patients with epilepsy and FOS persisting in adult life to better define the spectrum of syndromes. MethodsWe selected 15 consecutive patients (12 female/3 male; age range 19-59years). The main inclusion criterion was the diagnosis of epilepsy with FOS persisting in adult life. We retrospectively analyzed clinical EEG and neuroimaging data. Key FindingsWe observed a female prevalence (F/M=12/3). Eight patients presented both simple and complex partial seizures, whereas seven had only complex partial seizures. Partial seizures evolved into generalized seizures/hemiconvulsions in nine cases. The FOS pattern consisted of spike-and-wave and slow-wave abnormalities with posterior localization (bilateral in eight/monolateral in seven). We recorded seizures in 10/15 patients. All showed a posterior onset (bilateral in 2/left in 2/right in 6). FOS was prevalent in symptomatic epilepsy (cortical malformations in 7; celiac disease in 3; calcified vascular malformation in 1). One patient presented cryptogenic epilepsy and only three idiopathic epilepsy (Gastaut syndrome). SignificanceFOS can be observed in adult life in idiopathic epilepsy, representing the prolongation of the same phenomenon arisen during childhood. Nevertheless, it often represents the EEG expression of symptomatic epilepsies (cortical malformations/celiac disease)

Fixation-off sensitivity in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome

“…However we could not completely rule out the possibility of combined scotosensitivity, we used the term "FOS with or without scotosensivity" here. Although the underlying mechanisms remain still uncertain due to its rarity, FOS is thought to be modulated by α-rhythm generators and influenced by cortical hyperexcitability [4]. In MELAS syndrome, epileptic seizures occur primarily in association with stroke-like episodes, however, they can happen in patient with normal brain MRI like our patient.…”

“…Although FOS is rarely seen in the adult population, it often represents the EEG expression of symptomatic epilepsies (cortical malformations, celiac disease, calcified vascular malformation, and stroke, etc.) [4]. Strictly speaking, we should have differentiated FOS with scotosensitivity by the elimination of central vision/fixation in the presence of light with the use of modified Ganzfeld stimulation or Frenzel lenses.…”

Gluten sensitivity and epilepsy: a systematic review

“…The classification of the epilepsy presentations was reported in 45 of the articles [8, 10, 11, 13, 15, 16, 19–22, 25–30, 32, 33, 36, 38, 41–44, 48, 49, 51, 54, 56, 57, 60–69, 74, 75, 77, 81, 86–88,, 60–69, 74, 75, 77, 81, 86–88]. Of these, 25 could be used to calculate the prevalence of focal epilepsy amongst patients with epilepsy [8, 13, 15, 16, 18–21, 28, 33, 36, 41, 43, 45, 48, 51, 54, 56, 57, 61, 63, 65, 74, 87, 88].…”

The Spectrum of Epilepsies with Fixation off Sensitivity: A Case Report and Review of Literature

“…Koutromanidis, et al in the analysis of their videotelemetric data found both generalized and focal epilepsies contribute to the expanding repertoire of this evolving electroclinical syndrome [4]. The overwhelming contribution of the occipital lobe even in patients not fitting into the syndromic description of occipital lobe epilepsies of childhood was substantiated through the appraisal of electrical and functional imaging data by them and other investigators [4,6,7]. Secondary causes were excluded by imaging and celiac work up.…”

“…However, this electrographic finding is not specific for any of the entities within this broad and versatile category of epilepsies. There is a predilection for the younger age group [2][3][4][5][6]. This case report and ensuing discussion focuses on the clinical diagnosis, pathophysiology and differentials of this electro clinical syndrome.…”