Investigation of networks underlying hyperkinetic seizures utilizing ictal SPECT.

OBJECTIVE: To study neural networks involved in hyperkinetic seizures (HKS) using ictal SPECT. METHODS: We retrospectively identified 18 patients with HKS evaluated at the Cleveland Clinic between 2005 and 2015 with video-EEG monitoring and ictal SPECT. Semiology was confirmed by the consensus of 2 epileptologists' independent reviews and classified as type 1, 2, or 3 HKS. SPECT data were analyzed by 2 independent physicians using a z score of 1.5. Ictal hyperperfusion patterns for each group were analyzed visually and with SPM. Spatial normalization to Montreal Neurological Institute space for each patient's data was performed, followed by flipping of data from patients with left-sided ictal onset to the right side. Finally, an average z score map for each group was calculated. RESULTS: Visual analysis and SPM identified different patterns of ictal hyperperfusion in the 3 subtypes of HKS. Type 1 seizures showed hyperperfusion in a more anteriorly located network involving the anterior insula, orbitofrontal cortex, cingulate, and anterior perisylvian region and rostral midbrain. Type 2 seizures were associated with hyperperfusion in a more caudally located network involving the orbitofrontal cortex, cingulate (middle and posterior), basal ganglia, thalami, and cerebellum. Type 3 seizures showed a mixed pattern of SPECT hyperperfusion involving the temporal pole and anterior perisylvian region. CONCLUSIONS: Each of the 3 different semiologic subtypes of HKS is associated with distinct patterns of hyperperfusion, providing further insight into the neural networks involved. This knowledge may inform placement of invasive EEG electrodes in patients with HKS semiology undergoing presurgical evaluation.

Refractory focal motor seizures controlled with intramuscular botulinum toxin.

Patients with recurrent focal motor seizures present a management dilemma, as anti-convulsants are often ineffective, and resective surgery poses a high risk of motor deficit. We describe three patients with recurrent focal motor seizures that remained refractory despite numerous anti-convulsant trials. All patients showed either hyperperfusion on Single-Photon Emission Computerised Tomography (SPECT) or hypermetabolism on Positron Emission Tomography (PET) in primary motor cortex during periods of sustained jerking, although EEG abnormalities were uncommon. After botulinum toxin (BoT) injection there was a rapid and dramatic reduction in seizure frequency in all patients despite minimal limb weakness. Seizure freedom persisted for 3-6 months following treatment in the injected area. Repeat BoT injections following seizure recurrence were again efficacious in one case. Combining data from our cases with those previously reported, it appears that BoT may be a useful therapeutic tool for recurrent focal motor seizures. We hypothesise that the toxin disrupts or down-regulates an epileptic circuit between motor cortex and muscle, in which volleys of information from muscle spindles have been perpetuating seizure discharges in the cortex.

Brain activation patterns of versive, hypermotor, and bilateral asymmetric tonic seizures.

PURPOSE: Patients who have seizure onset from different brain regions can produce seizures that appear clinically indistinguishable from one another. These clinically stereotypic manifestations reflect epileptic activation of specific networks. Several studies have shown that ictal perfusion single photon emission computed tomography (SPECT) can reveal propagated ictal activity. We hypothesize that the pattern of hyperperfusion may reflect neuronal networks that generated specific ictal symptomatology. METHODS: All patients were identified who were injected with (99m)Tc-hexamethyl-propylene-amine-oxime (HMPAO) during versive seizures (n = 5), bilateral asymmetric tonic seizures (BATS; n = 5), and hypermotor seizures (n = 7) in the presurgical epilepsy evaluation between 2001 and 2005. The SPECT ictal­interictal difference image pairs of each subgroup were compared with image pairs of 14 controls using statistical parametric mapping (SPM 2) to identify regions of significant hyperperfusion. Hyperperfused regions with corrected cluster-level significance p < 0.05 were considered significant. RESULTS: We have identified a distinct ictal perfusion pattern in each subgroup. In versive seizure subgroup, prominent hyperperfusion was present in the frontal eye field opposite to the direction of head version. In addition, there was associated caudate and crossed cerebellar hyperperfusion. The BATS subgroup showed pronounced hyperperfusion supplementary sensorimotor area ipsilateral to the epileptogenic region, bilateral basal ganglia, and contralateral cerebellar hemisphere. The hypermotor seizure subgroup demonstrated two clusters of significant hyperperfusion: one involving bilateral frontomesial regions, cingulate gyri, and caudate nuclei, and another involving ipsilateral anteromesial temporal structures, frontoorbital region, insula, and basal ganglia. DISCUSSION: We have identified distinct hyperperfusion patterns for specific ictal symptomatology. Our findings provide further insight into understanding the anatomic basis of seizure semiology.

A hypermotor seizure with a focal orbital frontal lesion originating in the insula: a case report.

We present herein the case of a patient with a focal orbital frontal lesion on magnetic resonance imaging (MRI), but an insular onset of seizures. A 15-year-old boy suffered from hypermotor seizures for 9 years. In his seizures, he initially had a sensation that sounds were distant, and then his consciousness became impaired. After a short period of tonic activity, violent activities occurred, such as kicking or gripping some objects and shaking. MRI showed a focal cortical abnormality in the right orbital frontal lobe. [(18)F]FDG-PET revealed diffuse hypometabolism in the right frontal lobe, especially in the same site as the cortical lesion on MRI. The seizure onset zone was localized in the right anterior insula by intracranial recording. A resection of the right anterior insula and a partial disconnection of the frontal lobe were performed, rendering the patient seizure-free.

Cranial computed tomography in partial motor seizures.

OBJECTIVE: To identify the pattern of intracranial structural lesions in developmentally normal children with partial motor seizures by computed tomography and to monitor the behavior of single ring enhancing lesion (SREL) after a period of time with or without treatment. METHODS: Consecutive developmentally normal children between one year and twelve years with partial motor seizures in a tertiary care referral Hospital. After clinical examination and appropriate investigation for tuberculosis and cysticercosis, CT scan was performed. In addition to anticonvulsants, children received antituberculous or anticysticercal therapy if indicated. Repeat CT was performed on children with SREL after 6 months. RESULTS: Computed tomography was abnormal in 102 (68%) children. Majority of the children (75) had SREL. The lesions were located in decreasing order of frequency in the parietal lobe (65), frontal lobe (7), occipital lobe (1), temporal lobe (1) and cerebellum (1). Repeat CT scan was performed on 50 of the 75 children with SREL. Among these, in 41 children who were only on antiepileptic therapy, the SREL had decreased in size in thirty-two whereas in the rest (9), there was no change in the size. CONCLUSION: Awareness of the existence of disappearing SREL lesions is essential to avoid unnecessary treatment with antituberculous or anticysticercal therapy and provides ample justification in treating with anticonvulsant drugs only.