Quantitative and trajectory analysis of movement trajectories in supplementary motor area seizures of frontal lobe epilepsy

The objectives of this study were to quantitatively analyze the movement trajectories of four types of supplementary motor area (SMA) seizures (hyperkinetic, tonic posturing, fencing posture, tonic head turning), and to compare the movement trajectories of SMA seizures with those of temporal lobe seizures and psychogenic nonepileptic seizures. Ten video/EEG recordings of each type of seizure were obtained. Imaging data collected by video/EEG monitoring were transformed into a digital matrix with image processing software and then transformed into a movement trajectory curve with MATLAB 6.5 software. From these movement trajectories, amplitude, frequency, proximal/distal limb amplitude ratios, and shoulder/abdominal amplitude ratios measurements were calculated. One-way ANOVA revealed statistically significant differences in average amplitude, as well as proximal/distal limb amplitude ratios, in SMA seizures when compared with those of temporal lobe seizures and psychogenic nonepileptic seizures. This study proved the feasibility of quantitative analysis of SMA seizures and suggests it should be further evaluated for its capability to distinguish different seizure semiologies for the diagnosis of epilepsy.

Interobserver Reliability of Video Recording in the Diagnosis of Nocturnal Frontal Lobe Seizures

BACKGROUND

Nocturnal frontal lobe seizures (NFLS) show one or all of the following semeiological patterns: (1) paroxysmal arousals (PA: brief and sudden recurrent motor paroxysmal behavior); (2) hyperkinetic seizures (HS: motor attacks with complex dyskinetic features); (3) asymmetric bilateral tonic seizures (ATS: motor attacks with dystonic features); (4) epileptic nocturnal wanderings (ENW: stereotyped, prolonged ambulatory behavior).

OBJECTIVE

To estimate the interobserver reliability (IR) of video-recording diagnosis in patients with suspected NFLS among sleep medicine experts, epileptologists, and trainees in sleep medicine.

METHODS

Sixty-six patients with suspected NFLS were included. All underwent nocturnal video-polysomnographic recording. Six doctors (three experts and three trainees) independently classified each case as "NFLS ascertained" (according to the above specified subtypes: PA, HS, ATS, ENW) or "NFLS excluded". IR was calculated by means of Kappa statistics, and interpreted according to the standard classification (0.0-0.20 = slight agreement; 0.21-0.40 = fair; 0.41-0.60 = moderate; 0.61-0.80 = substantial; 0.81-1.00 = almost perfect).

RESULTS

The observed raw agreement ranged from 63% to 79% between each pair of raters; the IR ranged from "moderate" (kappa = 0.50) to "substantial" (kappa = 0.72). A major source of variance was the disagreement in distinguishing between PA and nonepileptic arousals, without differences in the level of agreement between experts and trainees.

CONCLUSIONS

Among sleep experts and trainees, IR of diagnosis of NFLS, based on videotaped observation of sleep phenomena, is not satisfactory. Explicit video-polysomnographic criteria for the classification of paroxysmal sleep motor phenomena are needed.

Effect of ACTH Therapy for Epileptic Spasms without Hypsarrhythmia

PURPOSE

We analyzed the short- and long-term effects of adrenocorticotropic hormone (ACTH) therapy for patients with epileptic spasms (ESs) who did not meet the criteria of West syndrome (WS).

METHODS

The subjects were 30 patients, including 13 boys and 17 girls, who had received ACTH therapy between 1970 and 2003. We excluded patients with WS, but included those with a history of WS who no longer showed hypsarrhythmia at the period of ACTH therapy. The age at onset of ESs and at ACTH therapy ranged from 2 to 82 months with a median of 18 months, and from 11 to 86 months with a median of 29 months, respectively.

RESULTS

Excellent and poor responses were obtained in 19 (63%) and 11 (37%) patients, respectively, as a short-term effect. Although the patients could be subclassified into five subgroups according to the previous reports, no difference was seen in short- term response to ACTH. Among 17 of the 19 patients with excellent short-term outcomes and a follow-up of >1 year after the ACTH therapy, eight patients have continued to be seizure free (29%; excellent long-term effect), whereas the remaining nine patients had a recurrence of seizures (complex partial seizures, four; generalized tonic seizures, three; ESs, two) at 9 months to 198 months (median, 49 months) after ACTH therapy. In addition, nine of the 17 patients demonstrated a localized frontal EEG focus after the ACTH therapy, although most of these had previously shown diffuse epileptic EEG abnormality.

CONCLUSIONS

ACTH therapy is worth trying for patients with resistant ESs, even without features of WS. However, the long-term effect is uncertain because recurrences of various types of seizures, including focal, were frequently observed.

Use of statistical parametric mapping of (18) F-FDG-PET in frontal lobe epilepsy

AIM

Evaluation of the use of statistical parametrical mapping (SPM) of FDG-PET for seizure lateralization in frontal lobe epilepsy.

PATIENTS

38 patients with suspected frontal lobe epilepsy supported by clinical findings and video-EEG monitoring.

METHOD

Statistical parametrical maps were generated by subtraction of individual scans from a control group, formed by 16 patients with negative neurological/psychiatric history and no abnormalities in the MR scan. The scans were also analyzed visually as well as semiquantitatively by manually drawn ROIs.

RESULTS

SPM showed a better accordance to the results of surface EEG monitoring compared with visual scan analysis and ROI quantification. In comparison with intracranial EEG recordings, the best performance was achieved by combining the ROI based quantification with SPM analysis.

CONCLUSION

These findings suggest that SPM analysis of FDG-PET data could be a useful as complementary tool in the evaluation of seizure focus lateralization in patients with supposed frontal lobe epilepsy.

Seizure semiology and neuroimaging findings in patients with midline spikes

PURPOSE

Midline epileptiform discharges are rare compared with discharges at other scalp locations. Neuroimaging results and semiologic seizure characteristics of patients with midline spikes are not adequately described. The aim of this study was to describe the neuroimaging findings and detailed seizure semiologies in patients with midline spikes.

METHODS

We reviewed the EEG database of the University of Michigan Medical Center and identified 35 patients with midline spikes. Information about seizure types and neuroimaging results was obtained from a review of medical records. The seizures were classified according to the International League Against Epilepsy (ILAE) criteria and semiologic classification.

RESULTS

Twenty-nine (83%) patients had a history of seizures. Complex partial seizures and simple partial seizures were the most common seizure types, experienced by 66% of patients. The age at seizure onset was within the first 10 years in 90% of patients. According to the semiologic seizure classification, automotor seizures and tonic seizures were the most common seizure types. Neuroimaging studies were abnormal in 45% of patients. When focal abnormalities were detected, they were lateralized to one of the frontal lobes in all cases.

CONCLUSIONS

Our results indicate that in the majority of patients, midline spikes represent focal epileptiform activity rather than fragments of generalized discharges, and are most commonly associated with seizures of partial onset. Automotor seizures and tonic seizures are the most common semiologies. Focal radiologic abnormalities tend to be lateralized to one of the frontal lobes.

Nonepileptic seizure outcome varies by type of spell and duration of illness

PURPOSE

To determine whether differences in clinical manifestations of psychogenic nonepileptic events are associated with differences in outcome and whether the length of illness before diagnosis correlates with outcome.

METHODS

We reviewed ictal videotapes and EEGs in 85 patients diagnosed with exclusively nonepileptic psychogenic seizures during inpatient CCTV-EEG monitoring at the University of Michigan between June 1994 and December 1996. They were classified into groups of similar ictal behaviors. Fifty-seven of these patients were available to respond to a follow-up telephone survey about their condition 2-4 years after discharge. We examined demographics, baseline EEG abnormalities, and outcome of treatment interventions. We also evaluated whether interventions were more likely to succeed if patients were diagnosed early in the course of the illness.

RESULTS

We found that the largest groups consisted of patients with motionless unresponsiveness ("catatonic," n = 19) and asynchronous motor movements with impaired responsiveness ("thrashing," n = 19). Infrequent signs included tremor, automatisms, subjective events with amnesia, and intermittent behaviors. There was a higher incidence of baseline EEG abnormalities in the thrashing group (31%) than in the catatonic group (0%). There was a higher incidence of complete remission of spells in the catatonic group (53%) than in the thrashing group (21%). Patients who had a more recent onset of seizures (most often within 1 year) were much more likely to have remission of spells after diagnosis.

CONCLUSIONS

Classification of nonepileptic seizures is useful in predicting outcome and may be valuable in further investigation of this complex set of disorders.

Frontal lobe epilepsy: the next frontier

Frontal lobe epilepsy, the great new epileptological challenge, presents enormous difficulties that still preclude a more profound understanding at the present time. The major subdivision of the frontal lobe into a prefrontal and premotor portion is the first step toward a better and yet limited comprehension of the frontal lobe epilepsies. Prefrontal implies higher mental functions (e.g., ictal forced thinking); rapid generalization to full grand mal evolves quite often from prefrontal foci. The frontal accentuation of classical generalized 3/sec spike-wave absences adds to the conceptual difficulties of the frontal lobe epilepsies. The unique type of disturbed consciousness in classical absences is presumed to be based upon ictal "suspension of the working memory." Limbic components (via orbitofrontal and cingulate mechanisms) also play an important role. Correlations between ictal semiologies and regional frontal lobe functions are still quite controversial.

Motor disorders in sleep

Sleep is normally a time of motor quiescence. Motor disorders may, however, arise during the different phases of sleep. Nocturnal myoclonus or periodic leg movements in sleep usually occur during light sleep and may be considered the motor accompaniment of the cyclic fluctuations in excitability typical of such stages. Nocturnal frontal lobe epilepsy also occurs during NREM sleep and may be misdiagnosed as parasomnia. REM behavior disorders are instead dissociated episodes of REM sleep without atonia, often associated with or even heralding Parkinson's disease or multiple system atrophy.

Nocturnal paroxysmal arousals with motor behaviors during sleep: frontal lobe epilepsy or parasomnia?

Nocturnal paroxysmal arousals with motor behaviors have been described in a few individuals, and their possible epileptic origin as nocturnal frontal lobe seizures has been suggested. However, the clinical and polysomnographic differentiation from parasomnias and physiologic movements during sleep have not been clarified yet. In this study, we evaluated a group of patients with nocturnal motor behaviors and tried to characterize paroxysmal arousals. Thirty-four participants (mean [+/-SD] age 22.7 [+/-12.9] years) noting nocturnal motor agitation or behaviors and 12 healthy controls (mean age 24.1 [+/-3.1] years) underwent nocturnal polysomnography with video-tape recording and motor behaviors analysis. Arousals with motor attacks were classified as minimal, minor, or major depending on semiology, complexity, and duration of behaviors. All patients showed several minimal (e.g., scratching or rubbing the nose and the head) and minor (e.g., pelvic thrusting or swinging with dystonic component) attacks, and 53% also had major episodes (e.g., sudden elevation of the head and trunk from the bed with complex behaviors) occurring mainly in non-rapid eye movement sleep. In all the patients, motor attacks were characterized by stereotypy, sudden onset, short duration, and repetitiveness. In 80%, epileptiform abnormalities were found. All control subjects showed motor events, but they were fewer, slower, nonstereotyped, and semiologically different from the patients'. No significant difference in conventional sleep parameters between the two groups were found. Paroxysmal arousals with motor behaviors probably represent a particular form of nocturnal frontal lobe epilepsy rather than an unusual parasomnia. The semiologic characteristics of these type of arousals are difficult to recognize and differentiate from physiologic movements or parasomnias without video-polygraphic analysis.

An analysis of clinical seizure patterns and their localizing value in frontal and temporal lobe epilepsies

The differentiation of frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) is a clinical problem of major theoretical and practical importance. Current electroclinical classification is based on retrospective studies of highly selected patients. When applied to the presurgical evaluation of patients, it has poor specificity. The current study adopts a different and prospective approach to the analysis of ictal clinical manifestations and their value in differentiating FLE and TLE. Two hundred and fifty-two patients with partial epilepsy were selected according to criteria of focal abnormality and imaging, ictal EEG or interictal EEG or highly focal clinical pattern. A witnessed seizure description was obtained for each of their habitual seizures and the sequence of manifestations encoded and entered into a statistical cluster analysis to form a clinical classification of the 352 seizures identified, which comprised 14 clinical groups. Neuroimaging abnormalities were measured, using a template technique, and graded 0-3 according to extent of involvement of each region in the lesion, using standard anatomical divisions. A chi 2 analysis of lesion location against seizure type was performed to assess the strength of association of seizure types with specific cerebral regions. The distribution of interictal EEG spikes and ictal EEG onsets were assessed qualitatively. An independent analysis was also performed, comparing clinical seizure manifestations associated with lesions restricted to either frontal or temporal lobes. Of the 14 clinical groups, four were predominantly related to temporal lobe abnormalities: fear/olfactory/gustatory; absence with no focal symptoms; experiential and visual. Within these groups, 45 out of 58 lesional cases involved the temporal lobes (P<<0.001). A minority of seizures in these groups were associated with frontal lesions and these seizures were significantly more likely to involve version/posturing, without an intervening absence phase, than the temporal cases (P<0.001). Two groups were related to perirolandic abnormalities; somatosensory and Jacksonian clonic with 22 out of 24 lesional cases involving this region (P<0.001). Two other groups were related to the frontal lobes; version/posturing and motor agitation. Early focal tonic activity or head turning were associated with lateral premotor lesions (P<0.001) and ictal and interictal EEG showed strong frontal predominance. Seizures characterized by general motor agitation were associated with lesions of the orbitofrontal (eight out of thirteen cases) and frontopolar (six out of thirteen cases) cortices (P<0.001). Location of interictal EEG spikes and ictal EEG onsets were generally consistent with lesion sites and where there were discrepancies, EEG localization tended to be more diffuse than lesion localization, rather than frankly discordant. Analysis of manifestations associated with pure frontal and pure temporal lesions supported the results of the cluster analysis and also showed a significant association of oro-alimentary automatisms with temporal lobe abnormalities. There were no consistent differences between groups with different localizations in terms of seizure frequency or other characteristics of seizure timing, although very high seizure frequencies were seen more often in association with frontal lesions. Only one combination of different seizure types in the same patient occurred with statistical significance: absence and generalized motor seizures and pseudo generalized epilepsy. The results of this study suggest that relatively few seizures can be localized reliably on clinical grounds and that even in those seizure types where there is a statistically significant association with specific cortical areas, an important minority do not share the same associations. Analysis of the seizure evolution as well as initial symptoms may be of value in localizing some cases, but even here wide variation occurs...

Hypnic tonic postural seizures in healthy children provide evidence for a partial epileptic syndrome of frontal lobe origin

In the pediatric age period, three idiopathic partial epileptic syndromes are recognized: benign childhood epilepsy with centrotemporal spikes, childhood epilepsy with occipital paroxysms, and primary reading epilepsy. All other partial epilepsies are considered cryptogenic, and no other idiopathic partial epilepsies have been recognized. We observed 10 children with tonic partial postural seizures, mainly hypnic, coinciding with a recognizable ictal epileptiform EEG pattern. The children all had normal neuropsychological development before and after seizure onset. The seizures were tractable in all. Onset was in the early pediatric age period; no other type of seizure was recognized. The occurrence of a family history of epilepsy was high. The seizure pattern was typical of supplementary motor area origin. Because of the normal neuropsychological status, high familial incidence of epilepsy, and benign course of this partial epilepsy, we believe it should be considered idiopathic, using the criteria of the International Classification of Epilepsies and Epileptic Syndromes. We therefore suggest the existence of a partial idiopathic epileptic syndrome having onset with seizures of frontal lobe origin.