Positive sharp waves in the EEG of children and adults
- 239 Downloads
Interictal epileptiform discharges (IEDs) with negative polarity have been extensively studied in the EEG literature. However, little attention has been drawn to IED with positive polarity [positive sharp waves (PSWs)]. In this paper, we discuss pathophysiological, neuroimaging, and clinical correlates of this pattern in a heterogeneous group of children and adults who demonstrated PSW in their scalp EEG. We prospectively reviewed the EEGs of 1,250 patients from a heterogeneous population over a period of 1 year. Thirty-one patients had PSW in their EEG. We documented EEG parameters as well as demographic, clinical, and neuroimaging data. Statistical analysis was performed to correlate the aforementioned data. The analysis showed that PSW is an epileptogenic pattern with localizing significance, occurring primarily in the younger age groups. Furthermore, there was a strong association of PSW with chronic and/or static CNS pathology, in particular, congenital CNS anomalies, often accompanied by psychomotor retardation. Patients with “multifocal’’ PSW invariably exhibited severe intellectual and motor deficits associated consistently with a variety of congenital CNS insults. PSW is a rare and under-reported EEG abnormality which, similar to negative IED, signifies focal epileptogenecity. The presence of PSW should prompt neuroimaging studies to investigate an associated chronic/static CNS pathology, in particular, congenital CNS anomalies. This association is particularly strong when PSW is multifocal in which case patients present with severe intellectual and motor deficits.
KeywordsPositive sharp waves (PSWs) Epilepsy EEG Epileptogenecity
Acknowledgment for the assistance of Jeffrey F. Ricablanca, Mary Grace Lorente, Abdulmohsen S. Alghassab.
- 3.Brazier MBA (1951) A study of the electrical fields at the surface of the head. Electroencephalogr Clin Neurophysiol: 38–52Google Scholar
- 8.Kellaway P, Hrachovy RA. Electroencephalography. In: Swaiman KF, Wright FS (eds) The practice of pediatric neurology, 2nd edn, pp 96–114Google Scholar
- 9.Lombroso CT (1981) Intracranial hemorrhage in the newborn. A prospective clinical and electrophysiological study of 37 cases. In: Proceedings of the IYDP commemorative International Symposium on developmental disabilities. Elsevier, Tokyo, pp 251–56Google Scholar
- 12.Maulsby RL (1971) Some guidelines for assessment of spikes and sharp waves in EEG tracings. Am J EEG Technol 11:3–16Google Scholar
- 14.Nowack WJ, Janati A, Antuago T (1987) Positive temporal sharp waves in the neonate. J Clin Neurophysiol 4:315–317Google Scholar
- 15.Nowack WJ, Janati A (1990) Positive sharp waves in neonatal EEG. Am J EEG Technol 30:211–221Google Scholar
- 16.Petsche H, Brazier MAB (eds) (1972) Synchronization of EEG activity in epilepsies. Springer-Verlag, New York, p 431Google Scholar
- 17.Purpura DP (1969) Stability and seizure susceptibility of immature brain. In: Jasper HH, Ward AA, Pope A (eds) Basic mechanisms of the epilepsies. Little, Brown and Co, Boston, pp 481–505Google Scholar
- 18.Seifer G, Blenkmann A, Princich JP et al. (2012) Noninvasive approach to focal cortical dystrophy. Epilepsy Res Treat. doi: 10.1155/2012/736784, Article ID 736784