ever, it does not question the v

However, it does not question the validity of electroclinical correlations between ictal manifestations and SEEG discharge, whenever the delineation of the epileptogenic area and the surgical decision are at stake. This observation confirms that any focal discharge has remote effects in a distributed network, which must be considered when analyzing the pathophysiologic mechanisms of ictal symptoms. 1Cf; n = 5) Six patients reported a sudden sensation of displacement of their body in space, such as a brisk forward projection, a vertical or horizontal rotation of their body, or a sensation of levitation. insular lesions epilepsy subtle optimizing mri detection suspected ajnr powerpoint figure tab open fig insula frontiersin seizures glimpse ecstatic epileptic roles multiple into figure fnbeh spect cerebral axial recordings subtemporal eeg cortex insular ecstatic seizures sensed Intracerebral implantation of electrodes and SEEG recording were selected on the basis of ictal symptoms or scalp video-EEG data suggesting an early spread of seizures either to the suprasylvian opercular cortex, such as lip and face paresthesiae or tonicclonic movements, laryngeal constriction, tonic or clonic movements of the face, dysarthria or motor aphasia, gustatory illusions, hypersalivation, postictal facial paresis (11, 12), or to the infrasylvian opercular cortex, such as auditory hallucinations or early sensory aphasia (13). Finally, the author would like to thank Editage (www.editage.com) for English language editing. Seizures began with laryngeal discomfort described as an unpleasant sensation of constriction (4A in Fig. See Ostrowsky et al. All illustrated seizures are simple partial seizures with complete preservation of contact during phases A, B, and C of the sequence. Of even greater concern, a misdiagnosis of paroxysmal nonepileptic spells (PNES) is also a possibilityone that can set the patient down a long and unnecessary course of diagnostic odyssey. The second seizure type was associated with a recruiting discharge of spikes in the hippocampus, followed by a low-voltage fast rhythmic activity in the posteroinferior (lead 3, arrow 2) and then in the antero- and posterosuperior insular quadrant. insular epilepsy arising cortex partial surgical treatment fissure The insula and its epilepsies. Ictal symptoms evoked by insular stimulation were multiple and consistent with perisylvian ictal symptoms such as somatosensory symptoms, including pain or laryngeal spasm, in addition to auditory, speech, vestibular, or olfacto-gustatory manifestations.31 Somatosensory ictal symptoms have been shown to manifest as paresthesia followed by pain and thermal sensations.32,33 Ostrowsky et al34 using insular stimulation, were the first investigators to describe pain as an insular cortex ictal symptom; the pain sensation was described as an electrical shock, burning, and painful pins and needles.34, Visceral ictal symptoms have been described as a constrictive sensation and discomfort in the laryngeal, retrosternal, or abdominal regions. Dysarthria and missing words during spontaneous speech (Fig. In this latter situation, as also observed in an anecdotal report of insular propagation of a frontal lobe discharge (23), the patient is usually unable to remember any of the subjective symptoms experienced during the seizure and to report them when the seizure is over. 1Cb and c). In five of them (cases 15), the seizures originated in the insula itself. Whole-body sensations (4% of the evoked responses; pink spots in Fig. 2. Methods: Since our first recordings of insular seizures, the insular cortex has been included as one of the targets of stereo-electroencephalographic (SEEG) electrode implantation in 50 consecutive patients with TLE whose seizures were suspected to originate from, or rapidly to propagate to, the perisylvian cortex. During the first 15 s of seizures, these discharges were undetectable at any other recording site outside the insula. A misdiagnosis of temporal lobe epilepsy or frontal lobe epilepsy is possible. Electric stimulation of the insula was able to reproduce symptoms that were immediately identified as identical to spontaneous ictal symptoms, such as lateralized widely distributed paresthesiae (patients 1, 3, 5, and 6), focal perioral paresthesiae (patients 2, 3, and 6), laryngeal sensation (patients 2, 4, and 5), or dysarthric speech (patient 5). Seizures with specific characteristics, including unpleasant somatosensory feelings, laryngeal constriction, hypersalivation, and dysphonic or dysarthric symptoms, are the most important manifestations of insular pathology.6 Seizures originating from the anterior insula may be asymptomatic at onset but may propagate and spread rapidly, leading to hypermotor symptoms, while posterior insular seizures will cause contralateral somatosensory symptoms.23, Goodkind et al24 recently published a meta-analysis on functional and other structural neuroimaging studies that showed a variety of insular abnormalities were associated with neuropsychiatric disorders such as depression, anxiety, addiction, autism, and schizophrenia.24-26 Insular lesions may also cause various cognitive, autonomic, and language dysfunctions.17,18,27 Despite the role of the insula in aphasia and language dysfunction being unclear, it has been found that language dysfunction is associated with dominant insular lesions.22 Different pathological lesions can cause insular symptoms, Chevrier etal. lobes cerebral Moreover, these five patients were precisely those with insular-onset seizures. There is a strong possibility of misdiagnosis if the treating physician does not consider the possibility of epilepsy of insular onset. EEG plays an important and crucial role in the diagnosis of epilepsy and seizure localization. Isnard J, Gunot M, Sindou M, Mauguire F. Clinical manifestations of insular lobe seizures: a stereoelectroencephalographic study. Ce, Dysarthric speech and missing words (cream white). insula cortex frontal insular operculum lobe sensory brain region located human reil neurosurgery operative which distinct recognized although bone skull bmj confusion seizure bilateral cranial mesial tomogram computed In addition to these ictal visceral symptoms, patients with insular epilepsy may experience salivation as well as facial blush and, less commonly, the urge to urinate and sweaty hands.33, The insular cortex is part of a complex epileptogenic network with multiple connections to different cortical and subcortical regions (Figure 2).35 For this reason, insular epilepsy is considered to be a great mimicker, because in addition to the perisylvian manifestations, it may present with temporal or frontal lobe ictal symptoms (Table 1). This procedure was performed immediately before SEEG electrodes removal and thus did not entail the risk of additional electrodes implantation. 1Cf; n = 6). A tailored cortectomy involving the temporal operculum and the inferior insula and a selective thermolesion of the insular focus were able to control seizures with a follow-up of 26 and 18 months in patients 1 and 3, respectively. (R, right; L, left). However, in spite of an ECoG strategy of exploring the insula systematically, Penfield et al. Insular epilepsy can be a great challenge to recognize. Malak et al52 described nine patients who underwent insular surgery due to refractory epilepsy; among them, seven patients had non-lesional insular epilepsy with an Engel Class IA outcome in six patients and an Engel Class III outcome in one patient.52 Alomar et al46 also reported a series of successful non-lesional insular epilepsy surgeries, with 33.3% of patients associated with an Engel Class I outcome, 40% with an Engel Class II outcome, 20% with an Engel Class III outcome, and 6.66% with an Engel Class IV outcome.Insular resection is generally safe, with mild and transient complications, except for some permanent motor deficits that can result from open resection of the caudal dorsal insula and adjacent parietal operculum.33,46 To avoid this possible motor complication, magnetic resonance imaging-guided stereotactic laser ablation to the dorsal caudal insula is an alternative and recommended safe procedure.33 In summary, the recent literature supports surgical interventions for lesional and non-lesional insular epilepsy, and should be considered in any drug-resistant insular epilepsy cases. Assistant Professor of Neurology 2), and the left shoulder before spreading to the left side of the body (1C in Fig. Moreover, heat, cold, and pain sensations were never evoked by stimulation of the parietal operculum. Ten ictal scalp EEG seizures were captured using video EEG recording. She had a second seizure type, during which she described a distressing ascending epigastric constriction associated with a hot flush. The choice to implant depth or subdural electrodes or both should be individualized to the specific patient.43-46. The borders of the insular lobe are drawn in red. Observation of this clinical sequence at the onset of seizures on video-EEG recordings in TLE patients strongly suggests that the seizure-onset zone is located not in the temporal but in the insular lobe; recording directly from the insular cortex should occur before making any decision regarding epilepsy surgery. Then the patient became progressively dysarthric until complete muteness, but still was able to perform simple tasks on verbal command. reviewed the structural abnormalities in 48 patients with insular/peri-insular cortex epilepsy and found neoplastic lesions in 27% of the patients, cortical malformations in 21%, vascular malformations in 19%, and encephalomalacia and atrophy in 17%.28 Moreover, other studies have reported etiologies for insular symptoms to include insular lesions such as low-grade brain tumors, vascular abnormalities including cavernomas, focal cortical dysplasia, and gliosis, the latter of which could be posttraumatic or related to an old brain insult.29,30, Isnard et al6 using intracranial monitoring with depth electrodes, were the first authors to analyze a special ictal manifestation in patients with insular epilepsy. Secondary propagation of insular discharges: to, temporal operculum; po, parietal operculum; fo, frontal operculum. Thirty-one of them were identified by the patients as identical to the ictal symptoms of their spontaneous seizures; 108 were reported as unknown and not similar to the usual ictal symptoms. Scalp EEG changes can be variable or misleading.3 Insular spikes simply may not be seen on scalp EEG. The afferent and efferent connections of the insula are summarized in Figure 2.16 Most of the insular functions were identified by cortical stimulation and, to a lesser extent, by functional magnetic resonance imaging (fMRI), especially with regards to language function. They found that the ictal onset in all three patients originated in the anterosuperior part of the insular cortex, indicating that the insula may play a major role in nocturnal hypermotor seizures.2. In TLE seizures, the auditory symptoms are currently attributed to ictal discharges in the temporal operculum and first temporal gyrus. The other types of IEDs were infrequent central or temporal discharges. Cb, Viscerosensitive responses are in blue, of which one was painful (in red). Then impressive hypersalivation occurred, followed by clonic jerks in the left arm and in the left side of the face (3D in Fig. The frequent IEDs were electronegative discharges over either the frontopolar or frontotemporal and mid-temporal regions. Insular surgical resection is generally safe, but it requires extensive presurgical workup and surgical precautions in order to minimize mortality. Stimulating the lower posterior part of the insula beneath the temporal operculum produced all but three of these auditory responses. subtle insular lesions epilepsy suspected mri detection optimizing ajnr powerpoint figure tab open fig 2). Patient 3 in Table 1 and Fig. Since 1996 we have included the insular cortex as a one of the targets explored by depth electrodes before surgery in TLE patients whose history, clinical seizures, and neuroimaging data did not fulfill all of the criteria for a diagnosis of mesial temporal lobe epilepsy (MTLE) (18), and whose ictal manifestations suggested a seizure propagation in the opercular suprasylvian cortex (11). epilepsy insular structural abnormalities peri spectrum frequency patients insula ajnr powerpoint figure tab open fig For this reason, auditory symptoms cannot be considered specific to insular ictal semiology. Studies with a good design were included in our review.

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