Effect of unilateral amygdalotomy and hypothalamotomy in patients with refractory aggressiveness.

BACKGROUND: Neurosurgical treatment, although controversial, is considered a useful resource in the treatment of chronic psychiatric diseases such as refractory aggressiveness. OBJECTIVE: To evaluate the clinical results and side effects of posteromedial hypothalamotomy associated with amygdalotomy in patients with refractory aggressiveness. METHOD: A clinical trial was conducted in patients with chronic aggressiveness and refractory to pharmacological treatment. A central amygdalotomy associated with posteromedial hypothalamotomy was performed using thermo-coagulation by radiofrequency. The degree of aggressiveness was quantified by the Yudofsky's global scale of aggression. Postoperative changes in aggressive behavior continued to be evaluated every 6 months for at least 36 months. RESULTS: A statistically significant change in aggressive behavior was observed during 36 months of follow-up. The collateral effects of the association of both procedures are described, the most frequent being drowsiness and some cases of reduction in sexual behavior. CONCLUSION: Symmetric and simultaneous unilateral lesions of the central nucleus of the amygdala and the posteromedial hypothalamus contralateral to motor dominance give the same clinical effect in the reduction of the pathological aggression that the bilateral lesions.

[Efecto de la amigdalotomía e hipotalamotomía unilateral en pacientes con agresividad refractaria].

BACKGROUND: Neurosurgical treatment, although controversial, is considered a useful resource in the treatment of chronic psychiatric diseases such as refractory aggressiveness. OBJECTIVE: To evaluate the clinical results and side effects of posteromedial hypothalamotomy associated with amygdalotomy in patients with refractory aggressiveness. METHOD: A clinical trial was conducted in patients with chronic aggressiveness and refractory to pharmacological treatment. A central amygdalotomy associated with posteromedial hypothalamotomy was performed using thermo-coagulation by radiofrequency. The degree of aggressiveness was quantified by the Yudofsky's global scale of aggression. Postoperative changes in aggressive behavior continued to be evaluated every 6 months for at least 36 months. RESULTS: A statistically significant change in aggressive behavior was observed during 36 months of follow-up. The collateral effects of the association of both procedures are described, the most frequent being drowsiness and some cases of reduction in sexual behavior. CONCLUSION: Symmetric and simultaneous unilateral lesions of the central nucleus of the amygdala and the posteromedial hypothalamus contralateral to motor dominance give the same clinical effect in the reduction of the pathological aggression that the bilateral lesions.

ANTECEDENTES: El tratamiento neuroquirúrgico, aunque polémico, se considera un recurso útil en el tratamiento de enfermedades psiquiátricas crónicas como la agresividad refractaria. OBJETIVO: Evaluar los resultados clínicos y los efectos colaterales de la hipotalamotomía posteromedial (HPM) asociada a amigdalotomía en pacientes con agresividad refractaria. MÉTODO: Se realizó un ensayo clínico en pacientes con agresividad crónica y refractaria a tratamiento farmacológico. Se les realizó amigdalotomía central asociada a HPM mediante termocoagulación por radiofrecuencia. El grado de agresividad se cuantificó mediante la escala global de agresividad de Yudofsky. Los cambios postoperatorios en la conducta agresiva continuaron siendo evaluados cada 6 meses durante al menos 36 meses. RESULTADOS: Se observó un cambio estadísticamente significativo de la conducta agresiva, a lo largo de 36 meses de seguimiento. Se describen los efectos colaterales de la asociación de ambos procedimientos, siendo el de mayor frecuencia la somnolencia y algunos casos de reducción en la conducta sexual. CONCLUSIÓN: Las lesiones unilaterales simétricas y simultáneas del núcleo central de la amígdala y del hipotálamo posteromedial contralaterales a la dominancia motora dan el mismo efecto clínico en la reducción de la agresividad patológica que las lesiones bilaterales.

[Treatment of refractory aggressiveness by amygdalotomy and posteromedial hypothalamotomy by radiofrequency]. / Tratamiento de la agresividad refractaria mediante amigdalotomia e hipotalamotomia posteromedial por radiofrecuencia.

INTRODUCTION: Since, under certain circumstances, defensive or attacking behaviours display a pattern of motor dominance, as observed in subjects who participate in contact or fighting sports, aggressive behaviour was considered to have a dominant motor pattern. With the aim of preventing the functional problems reported with bilateral lesion procedures involving both the central nucleus of the amygdala and the posteromedial hypothalamus, the decision was made to combine them; thus, an amygdalotomy of the central nucleus of the amygdala and a posteromedial hypothalamotomy were to be performed simultaneously and unilaterally, on the basis of the motor dominance of the patient determined by means of the Edinburgh test. PATIENTS AND METHODS: This study describes the surgical experience in a series of nine patients diagnosed with refractory neuroaggressive syndrome. As part of the study protocol, a magnetic resonance brain scan was performed to rule out the presence of neoplasms, vascular diseases, infections and degenerative disorders. The degree of aggressiveness was quantified using Yudofsky's Overt Aggression Scale. Additionally, manual dominance was determined by means of the Edinburgh test. RESULTS AND CONCLUSIONS: Good control of aggressiveness was seen immediately. In some cases it was necessary to reduce the antipsychotic or benzodiazepine medication, as it was seen to increase aggressiveness. Only one case required a second surgical intervention. Follow-up was achieved in 100% of the cases at 24 months and 78% at 36 months.

TITLE: Tratamiento de la agresividad refractaria mediante amigdalotomia e hipotalamotomia posteromedial por radiofrecuencia.Introduccion. Dado que, en algunas circunstancias, las conductas defensivas o de ataque muestran un patron de dominancia motora, tal como se observa en los sujetos dedicados a los deportes de contacto o de lucha, se considero que la conducta agresiva tiene un patron motor dominante. Con el fin de evitar los problemas funcionales descritos con los procedimientos de lesion bilateral tanto del nucleo central de la amigdala como del hipotalamo posteromedial, se decidio combinarlos; es decir, realizar amigdalotomia del nucleo central de la amigdala e hipotalamotomia posteromedial de manera unilateral y simultanea, basandose en la dominancia motora del paciente mediante la prueba de Edimburgo. Pacientes y metodos. Este estudio muestra la experiencia quirurgica en una serie de nueve pacientes con el diagnostico de sindrome neuroagresivo resistente al tratamiento farmacologico. Dentro del protocolo de estudio, se les realizo resonancia magnetica cerebral para descartar la presencia de neoplasias, enfermedades vasculares, infecciones y trastornos degenerativos. El grado de agresividad se cuantifico mediante la escala global de agresividad de Yudofsky. Adicionalmente, se determino la dominancia manual a traves de la prueba de Edimburgo. Resultados y conclusiones. El buen control de la agresividad se observo de modo inmediato. En algunos casos fue necesario reducir la medicacion de antipsicoticos o benzodiacepinas, ya que aumentaban la agresividad. Solo un caso requirio una segunda cirugia. Se logro seguimiento del 100% de los casos en 24 meses y del 78% en 36 meses.

Amygdala and Hypothalamus: Historical Overview With Focus on Aggression.

Aggressiveness has a high prevalence in psychiatric patients and is a major health problem. Two brain areas involved in the neural network of aggressive behavior are the amygdala and the hypothalamus. While pharmacological treatments are effective in most patients, some do not properly respond to conventional therapies and are considered medically refractory. In this population, surgical procedures (ie, stereotactic lesions and deep brain stimulation) have been performed in an attempt to improve symptomatology and quality of life. Clinical results obtained after surgery are difficult to interpret, and the mechanisms responsible for postoperative reductions in aggressive behavior are unknown. We review the rationale and neurobiological characteristics that may help to explain why functional neurosurgery has been proposed to control aggressive behavior.

Efecto de la amigdalotomía e hipotalamotomía unilateral en pacientes con agresividad refractaria / Effect of tonsillotomy and unilateral hypothalamotomy in patients with refractory aggressiveness

Resumen Antecedentes: El tratamiento neuroquirúrgico, aunque polémico, se considera un recurso útil en el tratamiento de enfermedades psiquiátricas crónicas como la agresividad refractaria. Objetivo: Evaluar los resultados clínicos y los efectos colaterales de la hipotalamotomía posteromedial (HPM) asociada a amigdalotomía en pacientes con agresividad refractaria. Método: Se realizó un ensayo clínico en pacientes con agresividad crónica y refractaria a tratamiento farmacológico. Se les realizó amigdalotomía central asociada a HPM mediante termocoagulación por radiofrecuencia. El grado de agresividad se cuantificó mediante la escala global de agresividad de Yudofsky. Los cambios postoperatorios en la conducta agresiva continuaron siendo evaluados cada 6 meses durante al menos 36 meses. Resultados: Se observó un cambio estadísticamente significativo de la conducta agresiva, a lo largo de 36 meses de seguimiento. Se describen los efectos colaterales de la asociación de ambos procedimientos, siendo el de mayor frecuencia la somnolencia y algunos casos de reducción en la conducta sexual. Conclusión: Las lesiones unilaterales simétricas y simultáneas del núcleo central de la amígdala y del hipotálamo posteromedial contralaterales a la dominancia motora dan el mismo efecto clínico en la reducción de la agresividad patológica que las lesiones bilaterales.

Abstract Background: Neurosurgical treatment, although controversial, is considered a useful resource in the treatment of chronic psychiatric diseases such as refractory aggressiveness. Objective: To evaluate the clinical results and side effects of posteromedial hypothalamotomy associated with amygdalotomy in patients with refractory aggressiveness. Method: A clinical trial was conducted in patients with chronic aggressiveness and refractory to pharmacological treatment. A central amygdalotomy associated with posteromedial hypothalamotomy was performed using thermo-coagulation by radiofrequency. The degree of aggressiveness was quantified by the Yudofsky's global scale of aggression. Postoperative changes in aggressive behavior continued to be evaluated every 6 months for at least 36 months. Results: A statistically significant change in aggressive behavior was observed during 36 months of follow-up. The collateral effects of the association of both procedures are described, the most frequent being drowsiness and some cases of reduction in sexual behavior. Conclusion: Symmetric and simultaneous unilateral lesions of the central nucleus of the amygdala and the posteromedial hypothalamus contralateral to motor dominance give the same clinical effect in the reduction of the pathological aggression that the bilateral lesions.

Laser Interstitial Thermal Therapy for Mesial Temporal Lobe Epilepsy.

Approximately one-third of patients with epilepsy do not achieve adequate seizure control through medical management alone. Mesial temporal lobe epilepsy (MTLE) is one of the most common forms of medically refractory epilepsy referred for surgical management. Stereotactic laser amygdalohippocampotomy using magnetic resonance-guided laser interstitial thermal therapy (MRg-LITT) is an important emerging therapy for MTLE. Initial published reports support MRg-LITT as a less invasive surgical option with a shorter hospital stay and fewer neurocognitive side effects compared with craniotomy for anterior temporal lobectomy with amygdalohippocampectomy and selective amygdalohippocampectomy. We provide a historical overview of laser interstitial thermal therapy development and the technological advancements that led to the currently available commercial systems. Current applications of MRg-LITT for MTLE, reported outcomes, and technical issues of the surgical procedure are reviewed. Although initial reports indicate that stereotactic laser amygdalohippocampotomy may be a safe and effective therapy for medically refractory MTLE, further research is required to establish its long-term effectiveness and its cost/benefit profile. ABBREVIATIONS: ATLAH, anterior temporal lobectomy with amygdalohippocampectomyLITT, laser interstitial thermal therapyMRg-LITT, magnetic resonance-guided laser interstitial thermal therapyMTLE, mesial temporal lobe epilepsySAH, selective amygdalohippocampectomySLAH, stereotactic laser amygdalohippocampotomy.

Parabrachial-hypothalamic interactions are required for normal conditioned taste aversions.

Rats with bilateral excitotoxic lesions of the parabrachial nuclei (PBN) fail to acquire a conditioned taste aversion (CTA), yet they retain the ability to express a CTA learned prior to incurring the damage. Rats with bilateral electrolytic lesions of the lateral hypothalamus (LH) also have CTA learning deficits. The PBN have reciprocal neural connections with the LH. This suggests that these CTA deficits may be functionally related. Electrolytic lesions damage fibers of passage, as well as intrinsic neurons. Thus, these LH lesions might also interrupt reciprocal connections between the PBN and other ventral forebrain areas, such as the amygdala and bed nucleus of the stria terminalis. To distinguish the source of the LH-lesion deficit, we tested for CTA first after bilateral excitotoxic lesions of LH and subsequently with a second set of animals that had asymmetric excitotoxic PBN and LH lesions. The rats with bilateral excitotoxic LH lesions showed deficits when acquiring a postlesion CTA. The asymmetrical PBN-LH lesions not only slowed acquisition of a CTA but also sped up extinction. This implies that interaction between the two structures, at minimum, facilitates CTA learning and may have a role in its consolidation.

Stereotactic radiofrequency amygdalohippocampectomy for the treatment of temporal lobe epilepsy: do good neuropsychological and seizure outcomes correlate with hippocampal volume reduction?

Temporal lobe surgery bears the risk of a decline of neuropsychological functions. Stereotactic radiofrequency amygdalohippocampectomy (SAHE) represents an alternative to mesial temporal lobe epilepsy (MTLE) surgery. This study compared neuropsychological results with MRI volumetry of the residual hippocampus. We included 35 patients with drug-resistant MTLE treated by SAHE. MRI volumetry and neuropsychological examinations were performed before and 1 year after SAHE. Each year after SAHE clinical seizure outcome was assessed. One year after SAHE 77% of patients were assessed as Engel Class I, 14% of patients was classified as Engel II and in 9% of patients treatment failed. Two years after SAHE 76% of subjects were classified as Engel Class I, 15% of patients was assessed as Engel II and in 9% of patients treatment failed. Hippocampal volume reduction was 58±17% on the left and 54 ± 27% on the right side. One year after SAHE, intelligence quotients of treated patients increased. Patients showed significant improvement in verbal memory (p=0.039) and the semantic long-term memory subtest (LTM) (p=0.003). Patients treated on the right side improved in verbal memory, delayed recall and LTM. No changes in memory were found in patients treated on the left side. There was a trend between the larger extent of the hippocampal reduction and improvement in visual memory in speech-side operated.

Effects of unilateral hippocampus-amygdala-partial temporal lobe resection on auditory EEG/MEG responses: a case study.

Auditory orienting and discrimination were studied with combined multi-channel EEG and MEG recordings in a patient with unilateral amygdala-hippocampus-partial temporal lobe resection of the right hemisphere. The results revealed abnormalities of habituation in alerting- and orienting-related responses, and discrimination-related responses, elicited by auditory stimulation contralateral to the resected cerebral hemisphere. These results give support to the notions about the role of the amygdala and hippocampus in alerting and orienting, respectively, and of the temporal cortex in auditory discrimination.

Impaired recognition of scary music following unilateral temporal lobe excision.

Music constitutes an ideal means to create a sense of suspense in films. However, there has been minimal investigation into the underlying cerebral organization for perceiving danger created by music. In comparison, the amygdala's role in recognition of fear in non-musical contexts has been well established. The present study sought to fill this gap in exploring how patients with amygdala resection recognize emotional expression in music. To this aim, we tested 16 patients with left (LTR; n = 8) or right (RTR; n = 8) medial temporal resection (including amygdala) for the relief of medically intractable seizures and 16 matched controls in an emotion recognition task involving instrumental music. The musical selections were purposely created to induce fear, peacefulness, happiness and sadness. Participants were asked to rate to what extent each musical passage expressed these four emotions on 10-point scales. In order to check for the presence of a perceptual problem, the same musical selections were presented to the participants in an error detection task. None of the patients was found to perform below controls in the perceptual task. In contrast, both LTR and RTR patients were found to be impaired in the recognition of scary music. Recognition of happy and sad music was normal. These findings suggest that the anteromedial temporal lobe (including the amygdala) plays a role in the recognition of danger in a musical context.

A specific role for the human amygdala in olfactory memory.

The medial temporal lobe is known to play a role in the processing of olfaction and memory. The specific contribution of the human amygdala to memory for odors has not been addressed, however. The role of this region in memory for odors was assessed in patients with unilateral amygdala damage due to temporal lobectomy (n = 20; 11 left, 9 right), one patient with selective bilateral amygdala damage, and in 20 age-matched normal controls. Fifteen odors were presented, followed 1 h later by an odor-name matching test and an odor-odor recognition test. Signal detection analyses showed that both unilateral groups were impaired in their memory for matching odors with names, these patients were not significantly impaired on odor-odor recognition. Bilateral amygdala damage resulted in severe impairment in both odor-name matching as well as in odor-odor recognition memory. Importantly, none of the patients were impaired on an auditory verbal learning task, suggesting that these findings reflect a specific impairment in olfactory memory, and not merely a more general memory deficit. Taken together, the data provide neuropsychological evidence that the human amygdala is essential for olfactory memory.

Obesity-inducing amygdala lesions: examination of anterograde degeneration and retrograde transport.

Small lesions centered in the posterodorsal region of the medial amygdala resulted in excessive weight gains in female rats. Unilateral lesions were nearly as effective as bilateral lesions in the first 48 h after surgery (+21 to +32 g). Assessment of lesion damage was done by both qualitative evaluation and by a quantitative grid-point counting method. The critical sites for weight gain were the intra-amygdaloid bed nucleus of the stria terminalis and the posterodorsal medial amygdaloid nucleus. Incidental damage to the overlying globus pallidus was negatively related to weight gain. The cupric silver method for demonstrating axonal degeneration was applied to brains with obesity-inducing lesions. A dense pattern of degenerating terminals was found in the lateral septum, amygdala, ventral striatum, and ventromedial hypothalamus. Degeneration in the paraventricular nucleus of the hypothalamus was scarce or absent. Small retrograde tracer injections made in either the intra-amygdaloid bed nucleus of the stria terminalis or in the posterodorsal medial amygdaloid nucleus labeled cells in the amygdala, lateral septum, and hypothalamus, reciprocating the anterograde projections from the amygdala to these areas. The data suggest that subdivisions of the posterodorsal amygdala participate in the regulation of feeding in a manner that is similar to the better-known role of this part of the brain in mediating reproductive behavior. Although topographical differences may exist within the amygdaloid and hypothalamic subdivisions regulating these two sexually dimorphic behaviors, the relays engaged by feeding-related connections and those related to reproduction are remarkably parallel.

Effect of some convulsants on the protective activity of loreclezole and its combinations with valproate or clonazepam in amygdala-kindled rats.

Loreclezole (5 mg/kg) exerted a significant protective action in amygdala-kindled rats, reducing both seizure and afterdischarge durations. The combinations of loreclezole (2.5 mg/kg) with valproate, clonazepam, or carbamazepine (applied at their subprotective doses) also exhibited antiseizure effect in this test. However, only two first combinations occurred to be of pharmacodynamic nature. Among several chemoconvulsants, bicuculline, N-methyl-D-aspartic acid and BAY k-8644 (the opener of L-type calcium channels) reversed the protective activity of loreclezole alone and its combination with valproate. On the other hand, bicuculline, aminophylline and BAY k-8644 inhibited the anticonvulsive action of loreclezole combined with clonazepam. The results support the hypothesis that the protective activity of loreclezole and its combinations with other antiepileptics may involve potentiation of GABAergic neurotransmission and blockade of L-type of calcium channels.

Differential effects of amygdala lesions on early and late plastic components of auditory cortex spike trains during fear conditioning.

In auditory fear conditioning, pairing of a neutral acoustic conditioned stimulus (CS) with an aversive unconditioned stimulus (US) results in an enhancement of neural responses to the CS in the amygdala and auditory cortex. It is not clear, however, whether cortical plasticity governs neural changes in the amygdala or vice versa, or whether learning in these two structures is determined by independent processes. We examined this issue by recording single-cell activity in the auditory cortex (areas Te1, Te1v, and Te3) of freely behaving, amygdalectomized rats using a movable bundle of microwires. Amygdala damage did not affect short-latency (0-50 msec) tone responses, nor did it interfere with conditioning-induced increases of these onset responses. In contrast, lesions of the amygdala interfered with the development of late (500-1500 msec) conditioned tone responses that were not present before conditioning. Furthermore, whereas onset conditioned responses in the control group remained elevated after 30 extinction trials (presentation of CS alone), onset responses in lesioned animals returned to their preconditioning firing level after approximately 10 extinction trials. These results suggest that the amygdala enables the development of long-latency (US anticipatory) responses and prevents the extinction of short-latency onset responses to threatening stimuli. The findings further suggest that auditory cortex cells may participate differently in explicit and implicit memory networks.

Differential modulation of changes in hippocampal-septal synaptic excitability by the amygdala as a function of either elemental or contextual fear conditioning in mice.

Recent data obtained using a classic fear conditioning paradigm showed a dissociation between the retention of associations relative to contextual information (dependent on the hippocampal formation) and the retention of elemental associations (dependent on the amygdala). Furthermore, it was reported that conditioned emotional responses (CERs) could be dissociated from the recollection of the learning experience (declarative memory) in humans and from modifications of the hippocampal-septal excitability in animals. Our aim was to determine whether these two systems ("behavioral expression" system and "factual memory" system) interact by examining the consequences of amygdalar lesions (1) on the modifications of hippocampal-septal excitability and (2) on the behavioral expression of fear (freezing) resulting from an aversive conditioning during reexposure to conditional stimuli (CSs). During conditioning, to modulate the predictive nature of the context and of a discrete stimulus (tone) on the unconditional stimulus (US) occurrence, the phasic discrete CS was paired with the US or randomly distributed with regard to the US. After the lesion, the CER was dramatically reduced during reexposure to the CSs, whatever the type of acquisition. However, the changes in hippocampal-septal excitability persisted but were altered. For controls, a decrease in septal excitability was observed during reexposure to the conditioning context only for the "unpaired group" (predictive context case). Conversely, among lesioned subjects this decrease was observed in the "paired group" (predictive discrete CS case), whereas this decrease was significantly reduced in the unpaired group with respect to the matched control group. The amplitude and the direction of these modifications suggest a differential modulation of hippocampal-septal excitability by the amygdala to amplify the contribution of the more predictive association signaling the occurrence of the aversive event.

[Stereotaxic amygdalotomy in the treatment of children with epilepsy]. / Stereotaksicheskaia amigdalotomiia v lechenii detei, bol'nykh épilepsiei.

Seventy four children with generalized and partial epileptic seizures were treated stereotactically. Local destruction of the amygdaloid complex was performed in 50 patients. It was combined with thalamotomy in 20 patients, and with campotomy in 4 patients. All cases were monitored intraoperatively by neurophysiologic techniques (e.g. EEG etc.). The follow up ranges from 1 to 17 years. When assessing the outcome, several factors were taken into consideration. Among those were the etiology, the stage of the disease, type of stereotactic procedure, and lateralization. Generally, positive results were obtained in 70% of cases.

[The comparative effect of melatonin and diazepam on shifts in the anxiety-phobia status of rats evoked by damage to the amygdala]. / Sravnitel'noe vliianie melatonina i diazepama na sdvigi v trevozhno-fobicheskom sostoianii krys, vyzvannye povrezhdeniem amigdaly.

Disorders develop in the emotional sphere in the form of increased anxiety and fear in amygdalectomized rats. The pineal hormone melatonin and diazepam (in an equal dose of 0.1 mg/kg) alleviate the state of anxiety and fear in the animals. Despite some differences in behavioral activity, the effect of the drugs appears to be similar. This suggests that melatonin possesses anxiolytic properties which may be related to its effect on the function of the limbic structures.

[The process of learning verbal material in patients with various damaged cerebral structures]. / Proces uczenia sie materialu slownego u chorych z uszkodzeniami róznych struktur mózgowych.

The results are described of a study of the process of verbal material learning and its recall after distraction in 20 patients with involuntary movements treated by thalamotomy, and in 20 epileptic patients treated by amygdalotomy and hippocampotomy. In both groups learning difficulties had been noted already before the operation. In postoperative tests these difficulties were found to have increased immediately after the surgical intervention in patients with lesions in the left cerebral hemisphere. On the other hand, late after the operation they were particularly pronounced after lesions placed in the right thalamus. Disturbances of material recall after distraction were shown in both groups independently of the side of the lesion.

Surgical treatment of epilepsy.

Seventy patients with intractable epilepsy were surgically treated. Thirty-three patients underwent a stereotactic procedure and in all as a first-stage operation fornicotomy was performed. Because of inadequate results in 14 patients, an additional stereotactic intervention was necessary; the targets were amygdala, thalamus, and Forel's H-field, and the final outcome of these patients was 9 (27%) seizure-free, 19 (58%) improved, and 5 (15%) unchanged. In 3 patients a selective amygdalo-hippocampectomy was performed with 2 seizure-free patients and one with improvement. Topectomy in focal epilepsy in 5 patients resulted in freedom from seizures in all cases. In 23 patients a lobectomy was performed; 10 (43%) were seizures-free, 8 (35%) were improved, and 5 (22%) were unchanged. In 6 patients only a pathological lesion was resected. Our results speak in favour of ablative surgery. However, stereotactic operations are indicated in cases with secondary generalization and dissipated foci on the dominant hemisphere.