CLINICAL ELECTROENCEPHALOGRAPHY
c’l992VOL 2 3 N 0 1
Changes In Reactivity During the 6/Second Spike and Wave Complex J. R. Hughes and J. J. Fino
Key Words
No study known to the authors has checked the responsiveness of patients during the 6SW. especially because the duration is usually < 1 sec, the pattern appears infrequently in any given record and has progressively become more rare in the past 3 O y e a r ~ .For ~.~ 3%decades the senior author has searched for a patient with a sufficiently long lasting and frequently occurring 6/sec spike and wave complex so that reactivity testing could be done during the complex. This report will summarize the data on the first patient found who would qualify for such a study.
Epilepsy Reaction Time 3/Sec. Spike and Wave Complex 6/Sec. Spike and Wave Complex
INTRODUCTION Bilaterally synchronous and symmetrical spike and wave complexes at 3/second (3SW) are well known to be associated with staring spells (absences) or changes in reactivity.’-3 Bilaterally synchronous and symmetrical spike and wave complexes at 6/second (6SW) are considered by some electroencephalographers to be a controversial pattern, but two distinctive forms have been described. One form is called by the acronym WHAM, associated with seizures and the other is called FOLD, associated with poorly-defined neurovegetative and psychiatric symptom^.^ The WHAM form refers to the pattern in Wake, High in amplitude, Anterior in location and usually found in Males. The FOLD form refers to the type usually found in Females, Occipital in location, Low in amplitude and seen in Drowsiness. Although clear clinical seizures are found in the great majority (82%) of patients with all aspects of the WHAM the greater prevalence of the FOLD form has resulted in some electroencephalographers still regarding all forms of the 6SW as controversial or even as a “benign EEG ~ a r i a n t .On ”~ the other hand, there are many characteristics that the 6/sec spike and wave complex has in common with the 3/sec spike and wave comp l e x : b o t h are bilaterally synchronous and symmetrical with a harmonic relationship in the frequency, both are either maximal on the frontal or posterior regions, and both can be activated by hyperventilation or photic Stimulation.‘ Furthermore, patients with the 6/sec form also show the 3/sec form in the same record with a significantly increased incidence.’ Finally, experience has shown that the 3/sec form in time may develop into the 6/sec form.
CASE REPORT This patient was a 37-year-old white female, who had her own successful professional practice. A family history of epilepsy included a brother with seizures and an uncle who died as the result of many seizures. Attacks in this patient began as generalized tonic-clonic seizures at the age of Byears, and continued until 16 years of age when they stopped while she was taking Zarontin 250 mg BID and phenobarbital 90 mg. At age 15, the patient began having brief (10sec) episodesof feeling intense fear with lip-smacking and had been placed on Dilantin l 0 0 m g QID, IaterreducedtoTIDwhen Mebaral was added at 50 mg TID. Tegretol was also attempted and was stopped when it seemed ineffective. In 1991, these episodes of fear occur as often as 5/day, especially just before menses, but usually average 20/mo. Diamox (250 mg each day) during the premenstrual period has been added and has reduced
John R Hughes M D Ph D is Director of EEG Directorof theEpilepsy Clinicand Prof of Neurologyat the Universityof Illinois at Chicago School of Medicine Chicago Illinois John J Fino B S E E is aResearch Biophysbcist in thesame Department of Neurology Requests for reprints should be addressed to Dr John R Hughes Department of Neurology University of lllinols at Chbcago M/C 796 912 South Wood Street Chicago Illinois 60612
31
Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
1992 VOL 23
CLINICAL ELECTROENCEPHALOGRAPHY
the number of these attacks. One other important clinical feature was the complaint of the patient that, especially during discussions with her professional contacts, she would occasionally miss a small portion of crucial information that was under discussion at that moment. Many EEGs have been done over a 30 year period, all showing the 6/sec spike and wave complex bilaterally synchronous and symmetrical, usually maximal on the frontal areas.
NO 1
Table 1 Durations of 6/sec spike &wave complexes Dur. (sec) 1.66
METHOD Two EEGs were taken in our laboratory with an 18-channel EEG machine and recording electrodes placed according to the 10-20 International System of Electrode Placement. Many 6SWs of relatively long duration were noted on the first record, so the patient agreed to return for the second record for testing responsiveness during the pattern. Table 1 shows the relatively long duration of these complexes in record #2. A click (50 db above threshold) was delivered through a small speaker placed 5 feet from the patient and served as the stimulus. The stimuli were presented as randomly as possible, but also an attempt was made to present them during the 6SW. The patient was instructed to press a hand-held button-switch as quickly as possible when she heard the stimulus. Both the stimulus and the response were recorded on the EEG paper (Figure 1). Latencies in msec were determined as a reaction t i m e (RT) between all stimuli and responses with an accuracy within 20 msec. Statistically significant differences between means were determined by a one-tailed Fisher’s Exact Test and differences in variability were determined by the F-test for homogeneity of variance.
No. 0 5 9 16 8 6 4 1 3 2
theta rhythms on the frontal areas without the spike component, (4) during the higher amplitude (>160 pV peak-peak) compared to lower amplitude (< 160 p V ) bursts, (5)after a delay (> 0.5 sec compared to < 0.5 sec) from the onset of 6SW and (6) during shorter ( 0.75 sec) durations of bursts. The longer latencies of stimuli presented during the wave were not quite statistically significant (p = 0.065) from those during the spike. Figure 1 shows examples of the latencies without the 6SW and also the longer latencies during and just after the pattern. Since a significant difference is seen between responses to stimuli > 0.5 sec after the onset of the burst, compared to < 0.5 sec, and also after the end of the 6SW, Figure 2 is presented to show the time course of these changes. This figure shows that within 0.5 sec after the onset of the 6SW. the 3 mean latencies decreased from 116% to 89%, but after 0.5 sec increased latencies were noted up to 147% at 0.75 sec, after which the values fell t o 120% at 1.6 sec. Thus, values around the end of the burst were still abovecontrol values, were 117%at 0.25sec beyond the end, finally coming down to near control values of 100% at 1.I sec after the termination of the burst. Figure 2 also shows the changes that were measured according to the time before the end of the burst. The dashed lineshowsthat around 1/3sec before theendof the burst, mean values wereclose to 140%, similar t o and likely related t o the value at 0.75 sec after the onset. However, the mean value was below 100% at 1.4 sec before the end of the burst, similar to and also likely related to the value below 100%around 0.5sec after the onset of the 6SW.
RESULTS In Table 2 the latency values are seen for the responses t o stimuli presented without the 6SW. From the49control values with a range of 199-423 msec, the mean of 293 msec (*40) was converted to 100% for a more meaningful and useful comparison with the values in the other conditions associated with the6SW. Although a response occurred with all stimuli, statistically significant differences f r o m these c o n t r o l values are seen in Table 2 by the longer latencies of response under various conditions. These include when the stimulus was: (1) during 6SW, (2) within 1 sec after 6SW, (3) during the bilaterally synchronous and symmetrical 32
Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
EE
1 ON62 10A2661, Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
‘a1992 VOL 23 NO 1
CLINICAL ELECTROENCEPHALOGRAPHY
Table 2
Latency changes in 6Isec spike and waves Condition Control
No.
During 6SW After 6SW During 0 During Wave During Spike During lo amp. During hi amp.
c’l992VOL 2 3 N 0 1
Changes In Reactivity During the 6/Second Spike and Wave Complex J. R. Hughes and J. J. Fino
Key Words
No study known to the authors has checked the responsiveness of patients during the 6SW. especially because the duration is usually < 1 sec, the pattern appears infrequently in any given record and has progressively become more rare in the past 3 O y e a r ~ .For ~.~ 3%decades the senior author has searched for a patient with a sufficiently long lasting and frequently occurring 6/sec spike and wave complex so that reactivity testing could be done during the complex. This report will summarize the data on the first patient found who would qualify for such a study.
Epilepsy Reaction Time 3/Sec. Spike and Wave Complex 6/Sec. Spike and Wave Complex
INTRODUCTION Bilaterally synchronous and symmetrical spike and wave complexes at 3/second (3SW) are well known to be associated with staring spells (absences) or changes in reactivity.’-3 Bilaterally synchronous and symmetrical spike and wave complexes at 6/second (6SW) are considered by some electroencephalographers to be a controversial pattern, but two distinctive forms have been described. One form is called by the acronym WHAM, associated with seizures and the other is called FOLD, associated with poorly-defined neurovegetative and psychiatric symptom^.^ The WHAM form refers to the pattern in Wake, High in amplitude, Anterior in location and usually found in Males. The FOLD form refers to the type usually found in Females, Occipital in location, Low in amplitude and seen in Drowsiness. Although clear clinical seizures are found in the great majority (82%) of patients with all aspects of the WHAM the greater prevalence of the FOLD form has resulted in some electroencephalographers still regarding all forms of the 6SW as controversial or even as a “benign EEG ~ a r i a n t .On ”~ the other hand, there are many characteristics that the 6/sec spike and wave complex has in common with the 3/sec spike and wave comp l e x : b o t h are bilaterally synchronous and symmetrical with a harmonic relationship in the frequency, both are either maximal on the frontal or posterior regions, and both can be activated by hyperventilation or photic Stimulation.‘ Furthermore, patients with the 6/sec form also show the 3/sec form in the same record with a significantly increased incidence.’ Finally, experience has shown that the 3/sec form in time may develop into the 6/sec form.
CASE REPORT This patient was a 37-year-old white female, who had her own successful professional practice. A family history of epilepsy included a brother with seizures and an uncle who died as the result of many seizures. Attacks in this patient began as generalized tonic-clonic seizures at the age of Byears, and continued until 16 years of age when they stopped while she was taking Zarontin 250 mg BID and phenobarbital 90 mg. At age 15, the patient began having brief (10sec) episodesof feeling intense fear with lip-smacking and had been placed on Dilantin l 0 0 m g QID, IaterreducedtoTIDwhen Mebaral was added at 50 mg TID. Tegretol was also attempted and was stopped when it seemed ineffective. In 1991, these episodes of fear occur as often as 5/day, especially just before menses, but usually average 20/mo. Diamox (250 mg each day) during the premenstrual period has been added and has reduced
John R Hughes M D Ph D is Director of EEG Directorof theEpilepsy Clinicand Prof of Neurologyat the Universityof Illinois at Chicago School of Medicine Chicago Illinois John J Fino B S E E is aResearch Biophysbcist in thesame Department of Neurology Requests for reprints should be addressed to Dr John R Hughes Department of Neurology University of lllinols at Chbcago M/C 796 912 South Wood Street Chicago Illinois 60612
31
Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
1992 VOL 23
CLINICAL ELECTROENCEPHALOGRAPHY
the number of these attacks. One other important clinical feature was the complaint of the patient that, especially during discussions with her professional contacts, she would occasionally miss a small portion of crucial information that was under discussion at that moment. Many EEGs have been done over a 30 year period, all showing the 6/sec spike and wave complex bilaterally synchronous and symmetrical, usually maximal on the frontal areas.
NO 1
Table 1 Durations of 6/sec spike &wave complexes Dur. (sec) 1.66
METHOD Two EEGs were taken in our laboratory with an 18-channel EEG machine and recording electrodes placed according to the 10-20 International System of Electrode Placement. Many 6SWs of relatively long duration were noted on the first record, so the patient agreed to return for the second record for testing responsiveness during the pattern. Table 1 shows the relatively long duration of these complexes in record #2. A click (50 db above threshold) was delivered through a small speaker placed 5 feet from the patient and served as the stimulus. The stimuli were presented as randomly as possible, but also an attempt was made to present them during the 6SW. The patient was instructed to press a hand-held button-switch as quickly as possible when she heard the stimulus. Both the stimulus and the response were recorded on the EEG paper (Figure 1). Latencies in msec were determined as a reaction t i m e (RT) between all stimuli and responses with an accuracy within 20 msec. Statistically significant differences between means were determined by a one-tailed Fisher’s Exact Test and differences in variability were determined by the F-test for homogeneity of variance.
No. 0 5 9 16 8 6 4 1 3 2
theta rhythms on the frontal areas without the spike component, (4) during the higher amplitude (>160 pV peak-peak) compared to lower amplitude (< 160 p V ) bursts, (5)after a delay (> 0.5 sec compared to < 0.5 sec) from the onset of 6SW and (6) during shorter ( 0.75 sec) durations of bursts. The longer latencies of stimuli presented during the wave were not quite statistically significant (p = 0.065) from those during the spike. Figure 1 shows examples of the latencies without the 6SW and also the longer latencies during and just after the pattern. Since a significant difference is seen between responses to stimuli > 0.5 sec after the onset of the burst, compared to < 0.5 sec, and also after the end of the 6SW, Figure 2 is presented to show the time course of these changes. This figure shows that within 0.5 sec after the onset of the 6SW. the 3 mean latencies decreased from 116% to 89%, but after 0.5 sec increased latencies were noted up to 147% at 0.75 sec, after which the values fell t o 120% at 1.6 sec. Thus, values around the end of the burst were still abovecontrol values, were 117%at 0.25sec beyond the end, finally coming down to near control values of 100% at 1.I sec after the termination of the burst. Figure 2 also shows the changes that were measured according to the time before the end of the burst. The dashed lineshowsthat around 1/3sec before theendof the burst, mean values wereclose to 140%, similar t o and likely related t o the value at 0.75 sec after the onset. However, the mean value was below 100% at 1.4 sec before the end of the burst, similar to and also likely related to the value below 100%around 0.5sec after the onset of the 6SW.
RESULTS In Table 2 the latency values are seen for the responses t o stimuli presented without the 6SW. From the49control values with a range of 199-423 msec, the mean of 293 msec (*40) was converted to 100% for a more meaningful and useful comparison with the values in the other conditions associated with the6SW. Although a response occurred with all stimuli, statistically significant differences f r o m these c o n t r o l values are seen in Table 2 by the longer latencies of response under various conditions. These include when the stimulus was: (1) during 6SW, (2) within 1 sec after 6SW, (3) during the bilaterally synchronous and symmetrical 32
Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
EE
1 ON62 10A2661, Downloaded from eeg.sagepub.com at University of Manitoba Libraries on June 17, 2015
‘a1992 VOL 23 NO 1
CLINICAL ELECTROENCEPHALOGRAPHY
Table 2
Latency changes in 6Isec spike and waves Condition Control
No.
During 6SW After 6SW During 0 During Wave During Spike During lo amp. During hi amp.
