Benign infantile focal epilepsy with midline spikes and waves during sleep: a new epileptic syndrome or a variant of benign focal epilepsy?

Abstract

To analyze the electroclinical features and evolution of seven infants with benign infantile focal epilepsy with midline spikes and waves during sleep (BIMSE). Material and methods. Seven patients were examined at our department between February 2003 and February 2009, with onset of seizures between six and 13 months of age (mean, 10.2 months; median, 11 months). Patients with cryptogenic and symptomatic focal epilepsies were excluded. Sex, age, familial history, type of seizures and AED treatment were noted and EEG monitoring, MRI and CT scanning, and developmental and psychomotor evolution were investigated. Results. Patients included five males and two females. All patients suffered from seizures during wakefulness. Two of the patients (29%) did not have a recurrence. Five (71%) had sporadic seizures (ranging between two and five). One of the seven patients (14%) presented with seizures in clusters. During seizures, staring was observed in six (86%), motion arrest in five (71%), stiffening in five (71%), cyanosis in three (42%), automatisms in one (14%) and lateralizing signs in four (57%). Two patients (29%) had secondary generalisation. The duration of the seizures ranged between 30 seconds and five minutes. No status epilepticus was observed. The interictal EEG recording during sleep showed low-voltage unilateral or bilateral spikes located in the central and vertex regions, followed by slow waves in all patients. Outcome was excellent in all patients. Conclusion. We believe that BIMSE is a new syndrome rather than an early presentation of benign epilepsy of childhood with centrotemporal spikes, Panayiotopoulos syndrome, or a late presentation of benign focal infantile seizures.

ILAE classification and definition of epilepsy syndromes with onset in neonates and infants: Position statement by the ILAE Task Force on Nosology and Definitions

“…The background EEG is normal, although focal slowing may occur postictally 55 . The interictal EEG is typically normal, but a variant with midline spikes during slow sleep has been described 56–58 . If there is persistent focal slowing in one area, a structural brain abnormality should be considered.…”

“…55 The interictal EEG is typically normal, but a variant with midline spikes during slow sleep has been described. [56][57][58] If there is persistent focal slowing in one area, a structural brain abnormality should be considered. Diffuse, persistent slowing would suggest a different syndrome.…”

Peri‐ictal EEG in infants with PRRT2‐related self‐limited infantile epilepsy

“…11 Previously, interictal EEG findings in PRRT2-related SeLIE have emphasized normal background activity without interictal epileptiform discharges, although midline spike-slow waves have been reported during sleep. 12,13 We observed peri-ictal EEG abnormalities in two infants with SeLIE, who later were confirmed to have pathogenic variants in the PRRT2 gene. This prompted us to review EEG findings in a larger group of infants with the same genetic diagnosis.…”

“…Interictal EEG markers can be useful in the early diagnosis of genetic epilepsies, for example the photoparoxysmal response at low stimulus frequencies in neuronal ceroid lipofuscinoses 11 . Previously, interictal EEG findings in PRRT2 ‐related SeLIE have emphasized normal background activity without interictal epileptiform discharges, although midline spike‐slow waves have been reported during sleep 12,13 …”

Benign infantile seizures and paroxysmal dyskinesia: A well-defined familial syndrome

“…Table 2 lists the syndromes associated with BIS. 2,26,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] In ICCA, epilepsy is characterized by focal or secondarily generalized seizures with onset in infancy and a benign prognosis, as observed in our cases. 2,17,18,20,21,24,26,45,47,50,53 PD has been divided into three categories: kinesigenic PD (PKD), non-kinesigenic PD (PNKD), and exercise-induced PD (PED).…”