Table 2 shows the number of analyzed videotaped seizures in each patient, seizure types, and focal features if present. A cluster of seizures was counted as one. Seventy-two seizures in 26 patients were analyzed. Focal semiologic features were observed in 12 (46%) of 46 patients.
Table 2. Semiology
|PT No.||Szs (n)||Seizure type and evolution||Focal features|
| 1|| 1||Myoclonic (bilateral arms), L versive GTC||L version|
| 2|| 3||L versive L arm clonic GTC, Myoclonic (bilateral arms) GTC||L arm clonic, L version, L Figure 4b|
| 3|| 2||Myoclonic (bilateral arms and legs), Myoclonic (bilateral arms) GTC||R Figure 4 b|
| 4|| 4||Myoclonic (bilateral arms, face), Myoclonic (bilateral arms, face) GTC||R Figure 4 b|
| 5|| 1||Myoclonic (bilateral arms) GTC||R Figure 4 b|
| 6|| 1||Myoclonic (axial)||Focal myoclonia|
| 7|| 4||Myoclonic (arm, neck, or shoulder) a, Dialeptic||Multifocal myoclonic|
| 8|| 2||Myoclonic (L arm), Dialeptic||Focal myoclonic|
| 9|| 2||Myoclonic (bilateral arms or L arm)||Focal myoclonic|
|10|| 9||Myoclonic (bilateral arms or L arm)||Focal myoclonic|
|11|| 3||Myoclonic (R arm), Myoclonic (bilateral arms) GTC||Focal myoclonic|
|12|| 1||Myoclonic (bilateral arms)||None|
|14|| 1||Myoclonic (bilateral arms)||None|
|15|| 3||Myoclonic (bilateral arms), Myoclonic (bilateral arms) Generalized clonic||None|
|17|| 4||Myoclonic (bilateral arms and face), Myoclonic (bilateral arms, face) GTC||None|
|18|| 1||Myoclonic (bilateral arms)||None|
|19|| 2||Myoclonic (axial > arm), Myoclonic (axial > arm) Generalized clonic||None|
|20|| 1||Myoclonic (face and shoulder)||None|
|21|| 1||Myoclonic (bilateral arms), Myoclonic (bilateral arms) GTC||None|
|23|| 2||Myoclonic (face, bilateral arms) GTC, Dialeptic||None|
|24|| 1||Myoclonic (bilateral arms) GTC||None|
|25|| 2||Myoclonic (bilateral arms)||None|
|26|| 1||R arm clonic GTC||R arm clonic, R Figure 4b|
Myoclonic seizures in 22 patients were analyzed. In four of them, myoclonic jerks were seen only immediately before a GTC seizure. In two patients, no clear myoclonic seizures were recorded, although they had a history of myoclonic jerks soon after awakening. One patient did not have a history of myoclonic jerks, but she was diagnosed as having JME because of generalized epileptiform discharges on EEG and a family history of JME. Another patient had myoclonic seizures during monitoring, but videos of them were unavailable for review. Myoclonic jerks involved arms in 18 cases, axial predominant in two, face and shoulders in one, and multifocal (arms, shoulders, or neck) in one. Facial involvement was seen in four cases. Legs were involved in one case. Myoclonic jerks culminated in a GTC or generalized clonic seizure in 11 patients.
Six patients had focal myoclonic seizures. In four patients, myoclonic jerks of unilateral arms were seen. Two of them had both unilateral and bilateral myoclonic jerks. One patient had a myoclonic jerk of the neck to the right side. Another patient had multifocal jerks of head, shoulders, or arms independently.
Dialeptic seizures were seen in six patients (patients 7, 8, 13, 16, 22, and 23). The duration was short (within 20 s) in five patients (patients 7, 8, 13, 16, and 22). They stopped what they were doing (reading, eating, throwing a ball, etc). Usually, clinical manifestations were very subtle and hard to notice. One of them had lip smacking associated with a dialeptic seizure. A relatively long (>40 s) phase of unresponsiveness was seen in patient 23.
Versive seizures were observed in two patients (patients 1 and 2). Two versive seizures were recorded in patient 2. The seizures were characterized by clonic turning of her head and eyes to the left, with a duration of 5–7 s, followed by a left-arm clonic seizure. Afterward, the left arm was extended tonically, and the right arm was flexed (Figure 4 sign), and generalized stiffening and jerking followed. In two seizures, the direction of the version was consistently to the left. In another patient (patient 1), one versive seizure was recorded. Turning of the head and eyes to the left was immediately followed by a GTC seizure.
A left-arm clonic seizure was transiently seen in patient 2, as mentioned earlier. Seventeen generalized motor seizures were seen in 13 patients. Fourteen of them were GTCs, and three were generalized clonic. These were preceded by myoclonic seizures in 11 cases. In two patients, these were preceded by versive seizures. In one patient who had both JME and left parietooccipital lobe epilepsy, it was preceded by right-arm clonic seizure. In GTC seizures, the generalized tonic phase was always preceded by very brief clonic phase.
Five patients, including one patient with left parietooccipital epilepsy, had asymmetrical tonic limb posturing during GTC seizures. In one patient (patient 2), the Figure 4 sign was seen immediately after a left versive seizure. Clusters of myoclonic jerks were followed by vocalization and asymmetrical tonic limb posturing in three patients. This asymmetry persisted during the whole tonic phase. Asymmetrical posture became gradually symmetrical during following clonic phase. In one of three patients, two GTC seizures were recorded. One GTC seizure exhibited the Figure 4 sign, and another was symmetrical. Postictal paresis or aphasia was not demonstrated in any patients.
In three patients who had both JME and focal epilepsy, two (patients 24 and 26) had both generalized and focal seizures recorded during monitoring. Fourteen automotor seizures were recorded in patient 24, but these were easily distinguishable from generalized seizures. Patient 26 also had two focal seizures recorded, and right-arm clonic seizure and Figure 4 sign were seen during a generalized EEG seizure. Another patient (patient 25) had no focal features in semiology.
Generalized nonepileptiform abnormalities were seen in 11 patients (Table 3). Generalized intermittent slowing was seen in five, intermittent rhythmic slowing in five, and background slowing in one. In patient 2, intermittent rhythmic slowing in the left parietal region was seen. Asymmetry was observed in two patients (patients 25 and 26) who had undergone craniotomies for treatment of their focal epilepsy. In patient 26, who had undergone a resection of a tumor in the left parietal lobe, intermittent slowing in the left temporoparietal region was seen. Interictally, all patients had generalized epileptiform discharges such as generalized spikes, polyspikes, spike–wave complexes, or combinations of these. Polyspikes were seen in 17 patients. Spike–wave complexes were seen in 22 patients. The frequency was fast (>3.5) in seven patients, ∼3 Hz (2.5–3.5) in 14, and slow (<2.5) in one.
Table 3. EEG
| PT no.||Nonepileptiform abnormalities|| IID|| Distribution||Ictal pattern|
| 1||None||Spike, polyspikes, SWC||Generalized||Polyspikes rhythmic alphaa|
| 2||IRS generalized and regional L parietal||Spike, SWC||Generalized||Spikes rhythmic delta rhythmic alpha a|
| 3||IS generalized||Fast SWC||Generalized||Fast SWC|
| 4||IS generalized||Spike, SWC||Generalized||Polyspikes electrodecrement|
| 5||None||Spike, polyspikes, SWC||Generalized maximum L||SWC|
| 6||None||Spike, polyspikes, fast SWC||Generalized||Fast SWC|
| 7||IRS generalized maximum R posterior||Spike, polyspikes, SWC||Generalized||Fast SWC|
| 8||None||Polyspikes, SWC||Generalized||Polyspikes, SWC|
| 9||None||Spike, polyspikes, fast SWC||Generalized||Fast SWC|
|10||IS generalized||Spike, polyspikes, SWC||Generalized||Polyspikes|
|11||IS generalized||Spike, fast SWC||Generalized||Spike, fast SWC|
|12||None||Spike||Generalized and L and R temporal||Spike, slow SWC|
|13||None||Spike, polyspikes, SWC||Generalized, R frontal||SWC|
|15||None||Spike, polyspikes, fast SWC||Generalized||Polyspikes electrodecrement|
|16||None||Spike, polyspikes, SWC||Generalized||SWC paroxysmal fast|
|17||None||Spike, polyspikes, fast SWC||Generalized||Fast SWC|
|18||IRS generalized||Spike, polyspikes, SWC||Generalized||Polyspikes|
|19||IS generalized||Spike, polyspikes, fast SWC||Generalized||Polyspikes, fast SWC|
|20||IRS generalized||SWC||Generalized||Slow SWC|
|21||None||Spike, polyspikes, SWC||Generalized||Polyspikes|
|22||None||Spike, polyspikes, SWC||Generalized||SWC|
|23||None||Spike, polyspikes||Generalized||Polyspikes, rhythmic theta-delta|
|24||BS||Spike||Generalized and L temporal||Polyspikes|
|25||IRS generalized, asymmetry increased beta R||slow SWC slow SWC||Generalized||Polyspikes|
|26||IS regional L T-P, asymmetry increased BG L||Spike||Generalized and R and L frontal||Polyspikes rhythmic delta|
One patient (patient 12) had sharp waves in left and right temporal regions in addition to generalized spikes interictally. He had no focal features in semiology. Another patient (patient 5) had generalized epileptiform discharges that were mostly maximum in the left. He exhibited the Figure 4 sign consisting of extension of the right arm and flexion of the left arm. In patient 13, a run of spikes in the right frontal region for 90 s was seen with no clinical signs (Fig. 1). Regional epileptiform discharges related to focal epilepsy were observed in two patients (patient 24 and 26), who had both focal epilepsy and JME.
The ictal EEGs of myoclonic seizures showed generalized patterns, except for one seizure. During myoclonic seizures, polyspikes were seen in 11 patients. In two of them, polyspikes were followed by electrodecrement. Fast spike–wave complexes were seen in seven, spike–wave complexes with frequency ∼3 Hz in three, and slow spike–wave complexes in two. In two patients (patient 11 and 12), single spikes were seen on EEG associated with myoclonic seizures. In one seizure, which started with a myoclonic seizure and evolved to a GTC seizure in patient 2, the ictal EEG showed generalized spikes followed by generalized delta slowing at first (Fig. 2A). But 9 s later, it revealed rhythmic alpha lateralized to the left hemisphere (Fig. 2B). Clinically, no focal features were observed in the seizure.
Figure 2. The ictal EEG of a myoclonic seizure evolving to a generalized tonic–clonic seizure in patient 2. A: EEG onset: Generalized spikes followed by generalized delta. B: Evolution: Rhythmic alpha lateralized to the left hemisphere appeared 9 s after EEG onset.
During dialeptic seizures in five patients, the ictal EEG showed generalized spike–wave complexes for 1 to 18 s. Because the duration of spike–wave complexes with no clinical signs ranges from 1 to 31 s, it is difficult to determine from the duration of the discharges whether the spike–wave complexes are symptomatic. In another patient who had a seizure with longer duration, generalized theta–delta activity for 44 s was seen during unresponsiveness.
The ictal EEG during two left versive seizures in patient 2 revealed generalized spikes followed by generalized rhythmic delta initially (Fig. 3A). Eighteen to nineteen seconds later, rhythmic alpha lateralized to the right hemisphere maximum in the right frontal region appeared (Fig. 3B). It evolved over the right hemisphere and then generalized. In semiology, she exhibited version to the left that was contralateral to the predominant EEG discharges.
Figure 3. The ictal EEG of a left versive seizure evolving to a generalized tonic–clonic seizure in patient 2. A: EEG onset: Generalized spikes followed by generalized delta. B: Evolution: Rhythmic alpha lateralized to the right hemisphere appeared 18 s after EEG onset.
The ictal EEG during a left versive seizure in another patient (patient 1) revealed generalized polyspikes followed by rhythmic alpha lateralized to the right hemisphere maximum in the right frontal region.
Except for seizures described earlier, the ictal EEGs during GTC or generalized clonic seizures showed generalized patterns.
Correlation of semiology and ictal EEG
In three versive seizures of two patients, the ictal EEGs revealed generalized onset and developed lateralized activity always contralateral to the direction of the version. In one of two patients (patient 2), a left-arm clonic seizure and Figure 4 sign also were observed.
In focal myoclonic seizures of six patients, the ictal EEGs showed generalized seizure patterns.
In four GTC seizures of four patients (patients 3, 4, 5, and 26) who exhibited Figure 4 sign, no regional epileptiform discharges in the ictal EEGs were seen. In one patient who had extension of the right arm and flexion of the left arm, interictal EEG revealed generalized epileptiform discharges mostly maximum in the left.
In two patients with no clinical focal features, focal EEG findings were observed. One patient had sharp wave in the left and right temporal regions. Another had a run of spikes in the right frontal region with no clinical signs.