Interictal aggression in epilepsy: the Buss-Durkee Hostility Inventory

Effects of perampanel on cognition and quantitative electroencephalography in patients with epilepsy

Antiepileptic drugs are well known for their effects on cognition and electrophysiologic changes. However, perampanel is yet to be evaluated for its effects on cognitive function and electroencephalography (EEG). The purpose of the present study was to identify the effect of perampanel on neuropsychological (NP) tests and quantitative EEG (QEEG) and their relationship with the level of the drug in blood. Seventeen patients with epilepsy were enrolled in the study. Electroencephalographic recordings were obtained, and NP tests were conducted before perampanel intake and 6 months after treatment. The relative frequency band power, peak alpha frequency, and NP test scores were compared before and after drug administration. The serum concentration of perampanel was correlated with the QEEG changes. Delayed recall of the Rey Complex Figure showed significant improvement (20.03 vs. 22.94; P = 0.004) following perampanel administration. Other cognitive function tests showed no significant differences before and after drug administration. Theta frequency band power increased in all brain regions (P = 0.001-0.01), and alpha frequency power decreased in all brain regions (P = 0.006-0.03). The theta/alpha ratio, which represents background EEG slowing, increased in all brain areas (P = 0.003-0.02). The peak frequency of the alpha rhythm decreased after perampanel intake (t = 2.45, P = 0.03). Difference of relative alpha power in the central region positively correlated with the blood level of perampanel (r = 0.53, P = 0.03). Perampanel induced electrophysiological slowing, but cognitive decline was not observed. Because the controls were not compared in the study, the results of cognitive function tests should be interpreted conservatively. Background EEG slowing correlated with the serum concentration of perampanel. Our results show the effect of perampanel on cognitive function and background EEG in adult patients with epilepsy.

Bilaterally Symmetrical: To Be or Not to Be?

We belong to a clade of species known as the bilateria, with a body plan that is essentially symmetrical with respect to left and right, an adaptation to the indifference of the natural world to mirror-reflection. Limbs and sense organs are in bilaterally symmetrical pairs, dictating a high degree of symmetry in the brain itself. Bilateral symmetry can be maladaptive, though, especially in the human world where it is important to distinguish between left and right sides, and between left-right mirror images, as in reading directional scripts. The brains of many animals have evolved asymmetries, often but not exclusively in functions not dependent on sensory input or immediate reaction to the environment. Brain asymmetries in humans have led to exaggerate notions of a duality between the sides of the brain. The tradeoff between symmetry and asymmetry results in individual differences in brain asymmetries and handedness, contributing to a diversity of aptitude and divisions of labor. Asymmetries may have their origin in fundamental molecular asymmetries going far back in biological evolution.

Evolution of cerebral asymmetry

The human brain is often characterized in terms of a duality, with the left and right brains serving complementary functions, and even individuals are sometimes classified as either "left-brained" or "right-brained." Recent evidence from brain imaging shows that hemispheric asymmetry is multidimensional, comprised of independent lateralized circuits. Cerebral asymmetries, which include handedness, probably arise in phylogenesis through the fissioning of ancestral systems that divided and lateralized with increasing demand for specialization. They also vary between individuals, with some showing absent or reversed asymmetries. It is unlikely that this variation is controlled by a single gene, as sometimes assumed, but depends rather on complex interplay among several, perhaps many, genes. Hemispheric asymmetry has often been regarded as a unique mark of being human, but it has also become evident that behavioral and cerebral asymmetries are not confined to humans, and are widespread among animal species. They nevertheless exist against a fundamental background of bilateral symmetry, suggesting a tradeoff between the two. Individual differences in asymmetry, moreover, are themselves adaptive, contributing to the cognitive and behavioral specializations necessary for societies to operate efficiently.

A new Italian instrument for the assessment of irritability in patients with epilepsy

The purpose of the work described in this article was to analyze the psychometric properties of a new Italian instrument for the assessment of irritability in adult patients with epilepsy (I-Epi). Five hundred four patients from nine secondary and tertiary Italian centers for the care of epilepsy were recruited and interviewed. Each patient was evaluated on a series of demographic and clinical variables recorded before administration of the I-Epi and the AQ (Aggression Questionnaire), used for external validity. The final results supported the reliability and validity of the I-Epi as a measure of irritability in the adult epilepsy population. The psychometric characteristics of the I-Epi seemed fairly good. We believe that adoption of this new instrument could be very useful in both clinical and research management of patients with epilepsy.

Characteristics of Epilepsy Patients who Committed Violent Crimes: Report from the National Forensic Hospital

Background and Purpose:

We investigated the clinical and criminal characteristics of patients with epilepsy who had committed violent crimes in order to understand the mechanism of violence and to prevent future criminal activity.

Methods:

We reviewed medical and legal reports of criminals with epilepsy who were incarcerated in the Korean National Forensic Hospital between October 2007 and September 2008.

Results:

Of 761 criminals admitted to the National Forensic Hospital, 17 patients (2.2%) were diagnosed with epilepsy. All of them had localization-related epilepsy, and no patient reported an overt seizure attack around the time of a crime. Psychosis was present in eight patients, and seven patients were in a drunken state at the time of the crimes. There was a positive correlation between the patients’ age at their first crime and their intelligence quotient score.

Conclusions:

These results suggest that most violent crimes take place during interictal periods, and diverse medical conditions, including inebriation, psychosis, and low intelligence, are associated with violent crimes among epileptic patients.

The evolution and genetics of cerebral asymmetry

Handedness and cerebral asymmetry are commonly assumed to be uniquely human, and even defining characteristics of our species. This is increasingly refuted by the evidence of behavioural asymmetries in non-human species. Although complex manual skill and language are indeed unique to our species and are represented asymmetrically in the brain, some non-human asymmetries appear to be precursors, and others are shared between humans and non-humans. In all behavioural and cerebral asymmetries so far investigated, a minority of individuals reverse or negate the dominant asymmetry, suggesting that such asymmetries are best understood in the context of the overriding bilateral symmetry of the brain and body, and a trade-off between the relative advantages and disadvantages of symmetry and asymmetry. Genetic models of handedness, for example, typically postulate a gene with two alleles, one disposing towards right-handedness and the other imposing no directional influence. There is as yet no convincing evidence as to the location of this putative gene, suggesting that several genes may be involved, or that the gene may be monomorphic with variations due to environmental or epigenetic influences. Nevertheless, it is suggested that, in behavioural, neurological and evolutionary terms, it may be more profitable to examine the degree rather than the direction of asymmetry.

A neuropsychiatry service in a state hospital. Adolf Meyer's approach revisited

In the spirit of Adolf Mayer's medico-biological approach to the understanding of mental illnesses the article describes the advantages that neuropsychiatric approach brings to the diagnostic evaluation and treatment of psychiatric patients in a state hospital. Our review discusses the neuropsychiatric approach to the evaluation of state hospital patients with mild, moderate, and severe cognitive disturbances showing the role of neuropsychological testing, electroencephalography (EEG), and brain imaging in the neuropsychiatric assessment of primary and secondary mental illnesses. Neuropsychiatric evaluation helps to assess the peculiarities of movement disorder as a of side effects of regular psychiatric medications, e.g. the differences in diagnostic signs and treatment implication between Parkinson's disease and extrapyramidal syndrome (EPS) as a side effect of neuroleptics as well as the development of abnormal reflexes as a sign of tardive dyskinesia (TD) not directly related to the lesion of upper motor neuron. The article also discusses the development of hypokinetic delirium in the course of treatment of psychiatric patients not only as a side effect of neuroleptics but also of anticonvulsants, increasingly used as the mood stabilizers in modern psychiatry. Since aggressive behavior of psychiatric patients represents one of the major criteria for admission and often long term treatment in a state hospital, special consideration is given to the role of brain paroxysmal activity in the development of aggressive behavior, especially rage attacks, one of the main manifestations of aggressive behavior in a state hospital patients. Correspondingly, the use of anticonvulsants in the treatment of rage attacks is discussed. This article may serve as a model for the use of neuropsychiatric service in improvement of diagnostic evaluation and treatment of psychiatric patients in a state hospital.

Cardiac Autonomic Control in Patients with Refractory Epilepsy before and during Vagus Nerve Stimulation Treatment: A One-Year Follow-up Study

PURPOSE

To elucidate possible effect of vagus nerve stimulation (VNS) therapy on interictal heart rate (HR) variability in patients with refractory epilepsy before and after 1-year VNS treatment.

METHODS

A 24-hour electrocardiogram (ECG) was recorded at the baseline and after 12 months of VNS treatment in 14 patients with refractory epilepsy, and once in 28 healthy age- and sex-matched control subjects. Time and frequency domain measures, along with fractal and complexity measures of HR variability, were analyzed from the ECG recordings.

RESULTS

The mean value of the RR interval (p=0.008), standard deviation of N-N intervals (SDNN) (p<0.001), very-low frequency (VLF) (p<0.001), low-frequency (LF) (p=0.001), and high-frequency (HF) (p=0.002) spectral components of HR variability, and the Poincaré components SD(1) (p=0.005) and SD(2) (p<0.001) of the patients with refractory epilepsy were significantly lower than those of the control subjects before VNS implantation. The nocturnal increase in HR variability usually seen in the normal population was absent in patients with refractory epilepsy. VNS had no significant effects on any of the HR-variability indexes despite a significant reduction in the frequency of seizures.

CONCLUSIONS

HR variability was reduced, and the nocturnal increase in HR variability was not present in patients with refractory epilepsy. One-year treatment with VNS did not have a marked effect on HR variability, suggesting that impaired cardiovascular autonomic regulation is associated with the epileptic process itself rather than with recurrent seizures.

Spatial learning deficits and emotional impairments in pentylenetetrazole-kindled rats

Pentylenetetrazole (PTZ) is a chemical kindling agent used to examine the efficacy of potential anticonvulsants in rats. However, the extent to which PTZ mimics postseizure symptoms of epilepsy has not been thoroughly examined. This study assessed whether PTZ-induced seizures produce cognitive and emotional deficits that mimic those observed in many epileptic patients. Rats were given 30mg/kg PTZ or vehicle (intraperitoneally) every other day for 28 days. Those rats exhibiting consistent seizure activity were tested for learning ability and emotional reactivity, beginning 1 week following a single challenge dose of PTZ. Rats given PTZ made more reference memory errors in a radial arm water maze task, and exhibited emotional abnormalities in the forced swim test, the systematic handling test, and the open-field exploratory maze. Histological analysis revealed neuronal loss in the CA1 area and increased mossy fiber sprouting in the dentate gyrus, similar to what is observed in human epilepsy. These results indicate that PTZ kindling provides a useful model of postseizure dysfunction, which can serve as a screen for potential treatments for those cognitive, emotional, and neuropathological deficits that resemble those symptoms observed in human epilepsy.

Psychiatric comorbidity in patients with epilepsy: implications for diagnosis and treatment

Psychiatric disorders frequently occur in patients with epilepsy but the diagnosis is frequently missed and therapeutic opportunities are often lost. These comorbidities assume greater importance as epidemiological data show their frequent association with impaired function and quality of life, and advances in neurobiology better define their pathophysiological relationship and therapies. Epilepsy presents a model for understanding psychiatric illness. Deciphering the role of different biological and environmental risk factors may help identify high-risk patients and allow for early intervention. Antiepileptic drugs are frequently used to manage psychiatric syndromes although the mechanisms of their psychotropic action remain uncertain. As recognition and treatment of comorbid psychiatric disorders in epilepsy remain suboptimal, we need to increase the awareness of physicians, patients, their caregivers, and the health care system. Better recognition will help to develop and implement appropriate diagnostic and treatment programs, and improve functional outcomes and quality of life in people with epilepsy.

Lateralised brain function in anurans: Comparison to lateralisation in other vertebrates

In recent years researchers have begun to investigate lateralisation of behaviour in amphibians. Given the mounting evidence of lateralisation in birds and mammals, and even reptiles, over the past two or more decades, it is not surprising that amphibians have attracted attention in this context. In particular, the evidence for lateralisation in fish has provided a strong basis for this research. This paper summarises the currently available information on lateralisation in anuran amphibians and discusses it in comparison to lateralisation in other vertebrate species, beginning with examples of motor lateralisation and then discussing functional asymmetries that occur between the left and right sides of the brain. The latter are manifested as side biases in responding to different stimuli or, in a number of non-amphibian species, revealed by monocular testing. Most of the examples discussed refer to lateralisation present at the level of the forebrain hemispheres, and so represent hemispheric specialisation. Lateralisation usually refers to examples in which there is a population bias for the majority of individuals in a population to be lateralised in the same direction. In other words, there is a significant skew in the frequency distribution. Such population biases in lateralisation are now known to be widespread among the vertebrates and, as shown, there are some surprisingly similar patterns of lateralisation in those species of fish, amphibians, reptiles, birds, and mammals that have been studied so far. It is also noted that, despite their ubiquity in vertebrates, far from all forms of lateralisation develop solely, or even largely, according to genetic determinants. In fact, the clear and powerful influences of environmental stimulation on development of some kinds of lateralisation in birds provide a basis for similar investigations in anurans.

Childhood epilepsy in relation to mental handicap and behavioural disorders

Epidemiological studies indicate that there is a high rate of mental retardation and behavioural problems in children with epilepsy. In some cases both the epilepsy and the mental retardation will have a common cause, such as a metabolic disorder or brain trauma. However, in other children, the epilepsy itself may cause either temporary or permanent learning problems. When permanent learning disability can be prevented it is important to treat the epilepsy early and effectively. Children with specific learning difficulties and memory problems can benefit greatly from appropriate management. There are many causes of behavioural disturbance in children with epilepsy. These causes include the epilepsy itself, treatment of the epilepsy, reactions to the epilepsy, associated brain damage/dysfunction and causes that are equally applicable to children who do not have epilepsy. Identifying the cause or causes in each child allows rational management to be provided. Antiepileptic treatment with medication or surgery can either improve the situation or make matters worse. The treatment should be tailored to the needs of the individual child. If surgery is required, there is a strong argument for performing this early in life, both to allow the greatest opportunity for brain plasticity and also to allow the child full benefit from the important developmental and educational years, without the problems that can be associated with the epilepsy. Skilled management of children with epilepsy who have mental retardation and/or behavioural problems can be very rewarding both for the family and for the professionals involved.

Bilateral medial prefrontal and temporal neocortical hypometabolism in children with epilepsy and aggression

PURPOSE

To identify brain regions with abnormal function in children with intractable partial epilepsy and aggressive behavior by using 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET).

METHODS

Six children (mean age, 9.9 years) with intractable partial epilepsy and aggressive behavior underwent detailed psychodevelopmental assessment and FDG-PET scanning. The objective technique of statistical parametric mapping (SPM) was applied to define focal abnormalities of glucose metabolism, and compared those with those of a group of normal adult subjects (n = 17) as well as age-matched children with epilepsy with similar seizure characteristics but without aggression (n = 7). The findings were analyzed further by using a region-of-interest (ROI) approach.

RESULTS

The aggressive children all showed developmental delay, and four of them also manifested autistic symptoms. SPM analysis demonstrated extensive glucose hypometabolism in the aggressive group bilaterally in the temporal and prefrontal cortex compared with that in normal adult controls. A focal area of medial prefrontal glucose hypometabolism was defined in the aggressive children as compared with the nonaggressive pediatric group with SPM, whereas ROI comparison of these groups confirmed prefrontal hypometabolism and also showed glucose hypometabolism of the temporal neocortex in the aggressive children. Severity of aggression correlated inversely with glucose metabolism of the left temporal as well as bilateral medial prefrontal cortex.

CONCLUSIONS

Bilateral prefrontal and temporal neocortical brain glucose hypometabolism in children with epilepsy and aggressive behavior may indicate a widespread dysfunction of cortical regions, which normally exert an inhibitory effect on subcortical aggressive impulses. PET studies may be used to elucidate the neurobiologic basis of aggressive behavior in children.

Long-term amygdala kindling in rats as a model for the study of interictal emotionality in temporal lobe epilepsy

Temporal lobe epileptics often experience profound interictal (i.e. between seizure) emotional disturbances, such as fear, anxiety, and depression. Although the presence of this interictal emotionality has been well documented, little progress has been made in identifying its precise nature and cause because it is not amenable to experimental analysis in clinical populations. Accordingly, there is much to gain by studying the fundamental nature and neural basis of interictal emotionality using animal models. Kindling is a widely studied animal model of temporal lobe epilepsy in which daily electrical stimulation of certain brain regions results in the gradual progression and intensification of limbic motor seizures. Several investigators have found that partial and short-term kindling produce robust changes in emotional behavior in both cats and rats. Recently, our laboratory has developed a new model to study interictal emotionality using long-term kindling in rats. These long-term kindled rats display profound changes in fearful and defensive behavior which last for at least two months after the final stimulation. We are now beginning to use this model to study the neural mechanisms underlying the development and expression of interictal emotionality.

Aggression and violence in patients with epilepsy

Violence has been associated with epilepsy. However, the links between violent behaviors and epilepsy involve multiple factors. These range from behaviors associated with underlying brain dysfunction to postictal delirious and psychotic states and rare cases of ictal aggression. This review describes the differential diagnosis of violent acts in epilepsy and the features that can be used to evaluate these behaviors.

Reduction of frontal neocortical grey matter associated with affective aggression in patients with temporal lobe epilepsy: an objective voxel by voxel analysis of automatically segmented MRI

BACKGROUND

Interictal episodes of aggression are often reported in patients with epilepsy. Some have characteristics of what has been referred to as episodic dyscontrol or intermittent explosive disorder (IED). Although structural brain abnormalities are thought to play a part in the pathophysiology of aggression, there are few in vivo studies of structural cerebral changes in patients with epilepsy and aggression. Using quantitative MRI, subtle structural brain abnormalities can be investigated in subgroups of patients with both epilepsy and episodes of affective aggression.

METHODS

After automated segmentation of cerebral grey matter from T1 weighted MRI, the objective technique of statistical parametric mapping (SPM) was applied to the analysis of 35 control subjects, 24 patients with temporal lobe epilepsy (TLE) with a history of repeated, interictal episodes of aggression, and 24 patients with TLE without episodes of aggression. Both TLE patient groups were compared with each other and with the control subjects on a voxel by voxel basis for increases and decreases of grey matter.

RESULTS

The patients with TLE with aggressive episodes had a decrease of grey matter, most markedly in the left frontal lobe, compared with the control group and with patients with TLE without aggressive episodes.

CONCLUSION

These findings suggest that a reduction of frontal neocortical grey matter might underly the pathophysiology of aggression in TLE. These voxel by voxel comparisons can guide further in vivo studies into aggression.

Cortical influences in emotion

Emotions may be classified into two major divisions: experience and behavior. Because the brain is critical for mediating emotional experience and behavior, diseases of the brain may induce changes in emotional behavior and experience. Disorders of almost all portions of the cerebral hemisphere, including the cortex, limbic system, and basal ganglia, have been associated with changes of emotional experience and behavior. Dysfunction of the cerebral cortex may be associated with disorders of emotional communication. Whereas deficits of the left hemisphere appear to impair the comprehension and expression of propositional language, deficits of the right hemisphere may be associated with an impaired ability to comprehend and express emotional gestures such as facial expression and emotional prosody. Some patients have either prosodic or facial emotional deficits. Some have only expressive or receptive deficits. However, others may be globally impaired, either within or across modalities. The posterior portions of the neocortex appear to be important for comprehension and the anterior for expression of both emotional prosody and faces. Injury and dysfunction of the limbic system may also alter emotional communication and experience. For example, damage to the amygdala may be associated with an impaired ability to recognized emotional faces and a reduction of affect, especially anger, rage, and fear. In contrast, lesions of the septal region may be associated with increased ragelike behaviors. Seizures frequently emanate from the limbic system, and seizures that start in the amygdala can induce fear and perhaps even rage. Disorders of the basal ganglia may also be associated with defects of emotional communication and experience. Patients with Parkinson's disease not only may be impaired at communicating emotions with both expressive and receptive deficits but also are often depressed and anxious. Patients with Huntington's disease may have emotional comprehension deficits with an impaired ability to recognize emotional faces and prosody. Patients with Huntington's disease may have mood changes even before motor dysfunction becomes manifest. Many of the defects in emotional experience may be related to the associated changes in neurotransmitter systems. Unfortunately, how alteration of neurotransmitters induce mood changes remains unknown. In this chapter we review the feedback and central theories of emotional experience. Although we argue against the postulates that feedback is critical to the experience of emotions, we do suspect that feedback may influence emotions. Emotions may be conditioned and may use thalamic-limbic circuits, as proposed by LeDoux. However, most emotional behaviors and experiences are induced by complex stimuli that an isolated thalamus could not interpret. The cerebral cortex of humans has complex modular systems that analyze stimuli, develop percepts, and interpret meaning. We discuss the proposal that the experience of emotions is dimensional. Almost all primary emotions can be described with two or three factors, including valence, arousal, and motor activation.