Case Report
Open Access
Six-Hertz Spike and Wave Epilepsy
Fermina Pirmohamed1*, Soundarya Gowda2
1Clinical Neurophysiology Fellow, Virginia Commonwealth University, Department of Neurology, Richmond VA, USA
2Assistant Professor of Neurology, Virginia Commonwealth University, Department of Neurology, Richmond VA, USA
2Assistant Professor of Neurology, Virginia Commonwealth University, Department of Neurology, Richmond VA, USA
*Corresponding author: Fermina Pirmohamed, Clinical Neurophysiology Fellow, Virginia Commonwealth University, Department of Neurology, Richmond
VA, 23298, USA, Tel: 804-828-9583; Fax: 804-828-6373; E-mail:
@
Received: February 10, 2016; Accepted: March 17, 2016; Published: April 11, 2016
Citation: Pirmohamed F, Gowda S (2016) Six-Hertz Spike and Wave Epilepsy. SOJ Neurol 3(1), 1-2. DOI: 10.15226/2374-6858/3/1/00121
AbstractTop
Introduction: A six-hertz spike and wave pattern has been
reliably described as a benign rhythm of reactivity and drowsiness
and occurs in 2.5% of adolescents and adults. Seizures are more
commonly derived from a higher frequency and larger amplitude
pattern on electroencephalography. This is a case of a six-hertz spike
and wave pattern associated withgeneralized tonic-clonic seizures
from a possible focus of cortical dysplasia.
Case Description: A nineteen-year-old male presented to the hospital after his second witnessed seizure. Seizure semiology is generalized tonic-clonic in nature and unprovoked. His neurologic examination was non-focal. His general examination and basic labs including an infectious work-up and full drug screen were negative. He was admitted for observation and found to have a sixhertz generalized spike wave pattern on his electroencephalogram. A contrasted MRI of the brain was performed and revealed a right frontal heterogeneous lesion adjacent to the anterior horn of the lateral ventricle. He was subsequently placed on an anti-epileptic medication and reports being seizure free at six-month follow-up.
Discussion: This case illustrates a patient where a six-hertz spike wave pattern is correlated with seizures and cortical dysplasia. Historically, a six-hertz spike wave pattern has been coined "phantom spike and wave" as it has been correlated with reactivity and known to be a rhythm of unknown significance. However, in the correct clinical circumstance, further investigation of this electroencephalographic pattern may be warranted in order to ensure appropriate therapy and management.
In this report we discuss a case of epileptic seizures associated with a benign six-hertz spike and wave electroencephalographic pattern originating from focal cortical dysplasia. A phantom six-hertz spike and wave pattern has not been reported in literature in relation to cortical dysplasia and epilepsy.
Keywords: Electroencephalogram (EEG); Neurophysiology; Cortical dysplasia; Epilepsy; 6-Hz spike wave; Seizure
Case Description: A nineteen-year-old male presented to the hospital after his second witnessed seizure. Seizure semiology is generalized tonic-clonic in nature and unprovoked. His neurologic examination was non-focal. His general examination and basic labs including an infectious work-up and full drug screen were negative. He was admitted for observation and found to have a sixhertz generalized spike wave pattern on his electroencephalogram. A contrasted MRI of the brain was performed and revealed a right frontal heterogeneous lesion adjacent to the anterior horn of the lateral ventricle. He was subsequently placed on an anti-epileptic medication and reports being seizure free at six-month follow-up.
Discussion: This case illustrates a patient where a six-hertz spike wave pattern is correlated with seizures and cortical dysplasia. Historically, a six-hertz spike wave pattern has been coined "phantom spike and wave" as it has been correlated with reactivity and known to be a rhythm of unknown significance. However, in the correct clinical circumstance, further investigation of this electroencephalographic pattern may be warranted in order to ensure appropriate therapy and management.
In this report we discuss a case of epileptic seizures associated with a benign six-hertz spike and wave electroencephalographic pattern originating from focal cortical dysplasia. A phantom six-hertz spike and wave pattern has not been reported in literature in relation to cortical dysplasia and epilepsy.
Keywords: Electroencephalogram (EEG); Neurophysiology; Cortical dysplasia; Epilepsy; 6-Hz spike wave; Seizure
Introduction
In this case report we would like to present a pattern of
six-Hertz spike and wave electroencephalographic pattern
associated with focal cortical dysplasia and heterotopia.
Case Report
A nineteen-year-old male presented to the hospital after
having his second witnessed seizure. His seizure was described
as arising out of wakefulness following a night of sleep
deprivation. He was witnessed to have generalized tonic clonic
activity at the onset without focality, with foaming at the mouth
for approximately three to four minutes after which he had
fifteen to twenty minutes of post-ictal fatigue without confusion.
He denied tongue biting, bowel or bladder incontinence and any
aura or prodrome. One year prior to this event, he had a similar
episode but details regarding workup were not known, and he
was not on any treatment. He has never had febrile seizures as
a child according to his mother and there is no family history of
epilepsy. He denied other potential provoking factors.
His neurologic examination was non-focal. His general examination and basic labs including an infectious work-up, electrolytes, liver function tests, urinalysis and full drug screen were also negative. A routine EEG showed six-hertz spike wave pattern as an interictal abnormality [Figure 1]. Specifically, it showed a symmetric and well-modulated background with brief, intermittent, frontally predominant six-hertz spike-wave discharges. The spikes were better formed with maximal surface negativity in the right frontal area. A contrasted MRI of the brain was performed revealing an area of heterotopia in the right frontal area adjacent to the anterior horn of the lateral ventricle with corresponding enlargement of the right temporal horn and tip with no evidence of hippocampal sclerosis or atrophy [Figure 1]. He was subsequently placed on an anti-epileptic medication and reports being seizure free on monotherapy of Keppra 1500mg twice a day at twelve-month follow-up.
His neurologic examination was non-focal. His general examination and basic labs including an infectious work-up, electrolytes, liver function tests, urinalysis and full drug screen were also negative. A routine EEG showed six-hertz spike wave pattern as an interictal abnormality [Figure 1]. Specifically, it showed a symmetric and well-modulated background with brief, intermittent, frontally predominant six-hertz spike-wave discharges. The spikes were better formed with maximal surface negativity in the right frontal area. A contrasted MRI of the brain was performed revealing an area of heterotopia in the right frontal area adjacent to the anterior horn of the lateral ventricle with corresponding enlargement of the right temporal horn and tip with no evidence of hippocampal sclerosis or atrophy [Figure 1]. He was subsequently placed on an anti-epileptic medication and reports being seizure free on monotherapy of Keppra 1500mg twice a day at twelve-month follow-up.
Discussion
A six-hertz spike and wave pattern has been reliably
described as a benign rhythm of reactivity and drowsiness that
occurs in 2.5% of adolescents and adults. It occurs during relaxed
wakefulness, drowsiness, stage I or light sleep and disappears
during deeper stages of sleep. This pattern manifests in
generalized bursts, predominantly symmetric and synchronous
over the anterior or posterior regions of the head depending on
gender. The morphology consists of sharp contoured positive
Figure 1: From left to right EEG shows frontally predominant 6-Hz spike and wave activity in a bipolar montage, a voltage map and voltage topography
shows a dipole that has maximal negativity in the right frontal area and axial and coronal T2 MRI images of the brain shows a corresponding
right peri-ventricular cortical dysplasia.
spikes alternating with rounded negative waves. They occur in
short runs usually lasting less than 5 seconds and as the name
would imply, the frequency is six hertz [1]. Demographically, it
occurs more often in women and in the third or fourth decade
of life [2]. Clinical correlates of this electroencephalographic
activity are thought to be head injury and excessive drug use,
although it has also been associated with psychiatric symptoms,
brain tumors, cerebrovascular disorders, post-traumatic
encephalopathies, cerebral degenerative diseases and other
central nervous system diseases [3,4]. Six-hertz spike and wave
activity was coined as "phantom" activity because it is thought to
be a normal physiological cerebral discharge. This is confirmed
by an extensive EEG survey of a large cohort of men in the US
army [2]. Furthermore, a study shows six-hertz spike and wave
bursts occurring during REM sleep, which would correspond to
its physiologic occurrence [5]. The EEG pattern is generalized in
nature and not derived from focal dysplasia or abnormality.
This case illustrates a unique presentation of a six-hertz spike and wave pattern occurring in concordance with generalized tonic-clonic seizures from a likely focus of cortical dysplasia. On EEG, the waveforms have a right frontal maximal surface negativity and are not truly generalized in distribution. These differences prompted further workup with neuroimaging and management was altered leading to better outcomes for this patient.
This case illustrates a unique presentation of a six-hertz spike and wave pattern occurring in concordance with generalized tonic-clonic seizures from a likely focus of cortical dysplasia. On EEG, the waveforms have a right frontal maximal surface negativity and are not truly generalized in distribution. These differences prompted further workup with neuroimaging and management was altered leading to better outcomes for this patient.
- Ebersole, J, TA Pedley. Current practice of clinical electroencephalography. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2003.
- Tharp B R. The 6-per-second spike and wave complex. The wave and spike phantom. Archives of neurology. 1966;15(5):533-537. doi:10.1001/archneur.1966.00470170087009.
- Silverman D, Theda Sannit. Clinical correlates of the spike-wave complex. Electroencephalography and clinical neurophysiology. 1954;6:663-669. doi:10.1016/0013-4694(54)90093-0.
- Hughes J R, R E Schlagenhauff, Margita Magoss. Electro-Clinical Correlations in the Six Per Second Spike and Wave Complex. Electroencephalography and clinical neurophysiology. 1965;18(1):71- 77. doi:10.1016/0013-4694(65)90148-3.
- Gelisse P, A Crespel. Phantom spike-and-wave bursts during REMsleep. Neurophysiologie clin. 2008;38(4):249-253. doi: 10.1016/j.