fMRI and cognitive dysfunction in schizophrenia

Despite being one of the most prevalent psychiatric conditions, SCHIZOPHRENIA is still poorly understood, with no clear objective biological marker. The advent of neuroimaging has enabled in vivo investigations to complement older techniques, and has revealed important insights. fMRI provides a means to assess the neurobiological theory that schizophrenia is caused by abnormal fronto-temporal lobe connections. In studies of language abnormalities, fMRI can explicitly assess the hypothesis that the normal lateralization of language is reversed in schizophrenia. Longitudinal fMRI studies, and studies examining the effects of medication, suggest that the technique has further potential to advance our understanding of this complex disorder.     

Neuropharmacological aspects of cognitive neurorehabilitation in epilepsy

The role of CNS neuromodulators in cognitive neurorehabilitation can be related to two main issues: 1) the negative impact on cognition of drug categories prescribed for different neurologic symptoms, such as spasticity, extrapyramidal symptoms, or epileptic seizures; 2) their possible role in neuroprotection and amelioration of the cognitive status of the patient, especially attention and memory. This paper reviews different pharmacological aspects of cognitive neurorehabilitation in epilepsy.     

Dichotic listening with forced attention in patients with temporal lobe epilepsy: significance of left hemisphere cognitive dysfunction

Fifty right-handed patients with focal temporal lobe epilepsy were administered a dichotic listening test with consonant-vowel syllables under non-forced, forced right and forced left attention conditions, and a neuropsychological test battery. Dichotic listening performance was compared in subgroups with and without left hemisphere cognitive dysfunction, measured by the test battery, and in subgroups with left and right temporal epileptic focus. Left hemisphere cognitive dysfunction led to more correct responses to left ear stimuli in all three attention conditions, and fewer correct responses to right ear stimuli in the non-forced attention condition. This was probably caused by basic left hemisphere perceptual dysfunction. Dichotic listening was less affected by a left-sided epileptic focus than by left hemisphere cognitive dysfunction. General cognitive functioning influenced dichotic listening performance stronger in forced than in non-forced attention conditions. Larger cerebral networks were probably involved in the forced attention conditions due to the emphasis on conscious effort.     

Reproductive dysfunction in women with epilepsy: antiepileptic drug effects on sex-steroid hormones

Women with epilepsy are at risk for reproductive health dysfunction. Sex-steroid hormone abnormalities have been reported in women with epilepsy, but it has been difficult to determine whether these abnormalities are due to epilepsy-related hypothalamic-pituitary axis dysfunction, or to pharmacokinetic actions of antiepileptic drugs (AEDs). Sex-steroid hormones were evaluated in 84 reproductive-aged women with epilepsy receiving an AED in monotherapy, and in 20 nonepileptic controls. Estrone, free testosterone, and androstenedione were significantly lower in subjects receiving enzyme-inducing AEDs than in nonepileptic controls. Free testosterone was significantly elevated in subjects receiving valproate compared to nonepileptic controls. Subjects with epilepsy receiving gabapentin or lamotrigine were no different from the nonepileptic controls in any of the endocrine variables. Subjects with epilepsy who are receiving AEDs that alter cytochrome P450 enzymes are at risk for significant abnormalities in sex-steroid hormones. In contrast, subjects receiving AEDs that do not alter cytochrome P450 enzymes show no differences in sex-steroid hormones compared with nonepileptic controls. With new AEDs available that do not alter cytochrome P450 enzymes, physician selection of therapy should consider not only seizure control, but also potential effects on reproductive physiology.     

Epileptic psychosis and nonconvulsive status epilepticus with ictal bradycardia and asystole

Case report of a 35 years old patient, who, without previous history of epilepsy, within two years experienced two long-lasting psychotic episodes due to non-convulsive status epilepticus with complex partial seizures. During the second psychotic episode she developed ictal vegetative phenomena such as profuse sweating, flush, apnoea, and, above all and most alarming, periods of severe bradycardia and asystolia with clinical signs of syncope. Ictal asystolia, though being an uncommon sing of epileptic seizures, may be one cause of sudden unexpected death in epileptics.     

A clinical comparative study evaluating the effect of epilepsy versus ADHD on timed cognitive tasks in children.

Both children with epilepsy and children with ADHD may be characterized by slowing on reaction-time measurement. This is of particular interest, as neuropsychological assessment is often requested in the differential diagnosis between children with short non-convulsive epileptic seizures and children with ADHD. In this study we attempt to identify patterns of impairment on timed tasks that are specific for epilepsy, relative to ADHD. This study was an open, controlled parallel-group clinical investigation which included two groups of patients: 60 children with ADHD and 60 children with epilepsy. These children were compared with a control group (n=30) on two types of timed cognitive tasks: tasks with low information load (simple reaction-time measurement) and tasks with high information load (multiple decision reaction-time measurement). The simple reaction-time measurements show significant differences between ADHD and controls (all except for visual RT non-dominant hand) and between epilepsy and controls (only one test). No significant differences were found between epilepsy and ADHD. The two tests with high information load show significant slowing compared with the controls for epilepsy on the Binary Choice Reaction-Time Test and for ADHD on the Visual Searching Test. On both tests also the differences between epilepsy and ADHD are significant. The two tests in combination have a relatively satisfactory potential to classify the children with ADHD (75% correct classification) and the children with epilepsy (55% correct classification). We may conclude that complex reaction-time tests (i.e., timed tasks with high information load) have potential for assessing the differential impact of ADHD and epilepsy on attentional function. These tasks specifically reveal general slowing for children with epilepsy and slowing as an effect of failures of inhibitory self control on unstructured tasks for ADHD.     

Enduring cognitive dysfunction in unipolar major depression: A test–retest study using the Stroop paradigm

Hammar, Å., Sørensen, L., Årdal, G., Oedegaard, K.J., Kroken, R., Roness, A. & Lund, A. (2009). Enduring cognitive dysfunction in unipolar major depression: A test–retest study using the Stroop‐paradigm. Scandinavian Journal of Psychology. The aim of the study was to investigate automatic and effortful information processing with the Stroop paradigm in a long term perspective in patients with major depressive disorder (MDD). Patients were tested at two test occasions: at inclusion with a Hamilton Depression Rating Scale (HDRS) score >18, and after 6 months, when most patients had experienced symptom reduction. The Stroop paradigm is considered to measure aspects of attention and executive functioning and consists of three conditions/cards: naming the color of the patches (Color), reading of the color‐words (Word) and naming the ink color of color‐words (Color‐Word). The Color‐Word condition is proved to be the most cognitive demanding task and requires the proband to actively suppress interference and is therefore considered to require more effortful information processing, whereas naming the color of the patches and reading the color‐words are expected to be more automatic and less cognitive demanding. A homogenous group of 19 patients with unipolar recurrent MDD according to DSM‐IV and a HDRS score of >18 were included in the study. A control group was individually matched for age, gender and level of education. Depressed patients performed equal to the control group on the Color and Word cards at both test occasions. However, the patients were impaired compared with the control group on the Color‐Word card task at both test occasions. Thus, the depressed patients showed no improvement of effortful attention/executive performance as a function of symptom reduction. The results indicate that the depressed patients showed impaired cognitive performance on cognitive demanding tasks when symptomatic and that this impairment prevailed after 6 months, despite significant improvement in their depressive symptoms.     

Psychoses in epilepsy

The heterogenous psychoses in epilepsies, caused by well known conditions, are not rare but associated with regularly a few of seizure-types not with the nature and development of attacks. Polar transitional ranks and converging courses of schizophrenic (accentuated) syndromes in epilepsies and idiopathic schizophrenias are rather frequent. Also (sub-)acute schizophrenic psychoses are corresponding to the complete palette of first and second rank symptoms (K. Schneider) of idiopathic schizophrenias. After manifestations of epilepsy these syndromes can appear at any time. It is given a profile of risks. Progressive avoidance of a. phenylaceturea, b. mixtures of antiepileptics did not put an end to psychotic syndromes: Long-term therapies with 1. Polytherapy, 2. Primidone and Phenytoin (dosedependant) as well as 3. Ethosuximide (-monotherapy) cause a disorder of feed back mechanisms, especially a disturbed regulation of vigilance and sleeping-waking-cycle and their psychological correlates. Carbamazepine and Sodium Valproate are, plasma-level-controlled of preventive antipsychotic effect. Selected neuroleptics of rather slight epileptogenic potency are of going down importance. Benzodiazepines are required mostly in prepsychotic syndromes, Lithium compounds in selected cases. There is no more alternative seizures or psychosis.     

Cortical malformations and epilepsy

Brain malformations, resulting from aberrant patterns of brain development, are highly correlated with childhood seizure syndromes, as well as with cognitive disabilities and other neurological disorders. The structural malformations, often referred to as cortical dysplasia, are extremely varied, reflecting diverse underlying processes and critical timing of the developmental aberration. Recent studies have revealed a genetic basis for many forms of dysplasia. Gene mutations responsible for such common forms of dysplasia as lissencephaly and tuberous sclerosis have been identified, and investigators are beginning to understand how these gene mutations interrupt and/or misdirect the normal developmental pattern. Laboratory investigations, using animal models of cortical dysplasia, are beginning to elucidate how these structural malformations give rise to epilepsy and other functional pathologies.     

Language in benign childhood epilepsy with centro-temporal spikes abbreviated form: rolandic epilepsy and language

Although Benign Childhood Epilepsy with Centrotemporal Spikes (BECTS) has a good prognosis, a few studies have suggested the existence of language disorders relating to the interictal dysfunction of perisylvian language areas. In this study, we focused on language assessment in 16 children aged 6-15 currently affected by BECTS or in remission. An important proportion of children showed moderate or more severe language impairment. The most affected domains were expressive grammar and literacy skills. We found linguistic deficits during the course of epilepsy but also persistent deficits in children in remission, suggesting possible long-term effects. Our results support the hypothesis that BECTS may be associated with impairment to language and suggest the possibility of a direct link between epileptic activity and language development, and the existence of long-term consequences.     

Stress-related cognitive interference predicts cognitive function in old age

Both subjective distress and cognitive interference have been proposed as mechanisms underlying the negative effects of stress on cognition. Studies of aging have shown that distress is associated with lower cognitive performance, but none have examined the effects of cognitive interference. One hundred eleven older adults (M-sub(age)=80) completed measures of working memory, processing speed, and episodic memory as well as self-report measures of subjective distress and cognitive interference. Cognitive interference was strongly associated with poorer performance on all 3 cognitive constructs, whereas distress was only modestly associated with lower working memory. The results suggest that cognitive process related to stress is an important predictor of cognitive function in advanced age.