Istvan Balas

University of Pécs, Fuenfkirchen, Baranya county, Hungary

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Publications (50)124.44 Total impact

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    Dataset: mattis3
  • Article: [Comment].
    Ideggyógyászati szemle 05/2013; 66(5-6):207. · 0.35 Impact Factor
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    ABSTRACT: Spinal cord stimulation has become an established clinical option for treatment of refractory chronic pain and angina pectoris, but its precise mechanism of action is unclear. We investigated the effect of spinal cord stimulation (SCS) on heart rate variability (HRV) and evaluating its influence on the sympathetic/parasympathetic balance in chronic pain. MATERIALS AND PURPOSE: Seven patients (three men, four women) with SCS due to chronic pain were included. The SCS was programmed in three different ways: (i) to stimulate at an amplitude known to generate paresthesias (ON-state), (ii) at a subliminal level (SUB state), or (iii) switched off (OFF-state). HRV analysis was based on 5-min segments of the consecutive normal RR intervals and was performed with custom software (Kubios HRV Analysis). The mean heart rate was higher in ON state compared to SUB state (p = 0.018) and the high-frequency component of the HRV was lower in ON compared to OFF period (p = 0.043). Other HRV parameters values did not significantly differ during the three tested periods. Spinal cord stimulation in chronic pain seems to be accompanied by reduced parasympathetic tone, unlike SCS in angina pectoris where previous studies found a reduced cardiac sympathetic tone. Our study might lead to understand the mechanism of action of SCS We investigated a relatively small number of patients, which is the main limitation of our study. Thus, further studies with larger number of patients are required for validation of our results.
    Ideggyógyászati szemle 03/2013; 66(3-4):102-6. · 0.35 Impact Factor
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    ABSTRACT: Bilateral pallidal deep brain stimulation (DBS) is an established treatment option for primary generalized and segmental dystonia. In the present study we evaluated the results of our dystonia patients treated by DBS. The surgical results of forty consecutive dystonia patients underwent DBS implantation were analyzed (age: 43.7 +/- 17.7 years; sex: 22 men; etiology: 24 primary and 16 secondary dystonia; topography: 24 generalized, 12 segmental and four hemidystonia; disease duration: 16.1 +/- 9.3 years). Severity of dystonia measured by Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and health-related quality of life measured by EQ-5D scale were obtained preoperatively and compared to the scores obtained at postoperative six months and subsequent yearly follow-ups. The average follow-up lasted 2.5 years (median, 0.5-8 years). In all cases the BFMDRS scores were re-evaluated by a rater blinded to the treatment. Treatment responsiveness was defined as an at least 25% improvement on the BFMDRS scores. Non-parametric Mann-Whitney, McNemar and Kruskal-Wallis tests were applied to test statistical significance. Severity of dystonia improved from 31 to 10 points (median, 68% improvement, p < 0.01) in the primary dystonia group, whereas in secondary dystonia these changes were statistically insignificant (improvement from 40 to 31.5 points, 21.2%, p > 0.05). However, the health-related quality of life significantly improved in both groups (primary dystonia: 0.378 vs. 0.788 and secondary dystonia: 0.110 vs. 0.388, p < 0.01). Significantly more patients in the primary dystonia group responded to DBS treatment than those in the secondary dystonia group (83.3% vs. 37.5%, p < 0.01). Our results are in accordance with previously published international findings demonstrating that DBS is a highly effective and long-lasting treatment option for primary dystonia. DBS is considerably less efficient in secondary dystonia; however, it still has a high impact on the quality of life presumably due to its pain-relieving effect.
    Ideggyógyászati szemle 07/2012; 65(7-8):249-60. · 0.35 Impact Factor
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    ABSTRACT: Status dystonicus (SD) is a rare, life-threatening disorder characterized by acute worsening of generalized dystonia. This study was conducted to characterize the pathogenesis, clinical course, and prognosis of SD. We reviewed the records of six centers and analyzed them together with all the cases previously reported in the literature. Eighty-nine episodes occurring in 68 patients were studied. The majority of patients were males (64.7%), were <15 years of age (58.8%), and had secondary dystonia as the underlying condition (37.8%). The episodes were mainly characterized by tonic muscle spasms (68.5%), with phasic forms more common in secondary forms and among females. Almost all cases needed a multistaged approach, with surgery being the most successful strategy. Neurological conditions preceding the episode worsened in 16.2% of cases (ending in death in 10.3%). The course and outcome of SD is highly variable; male gender and prevalent tonic phenotype predict a poor outcome.
    Movement Disorders 04/2012; 27(6):783-8. · 5.63 Impact Factor
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    ABSTRACT: Among the non-motor features of Parkinson's disease (PD), cognitive impairment is one of the most troublesome problems. Highly sensitive and specific screening instruments for detecting dementia in PD (PDD) are required in the clinical practice. In our study we evaluated the sensitivity and specificity of different neuropsychological tests (Addenbrooke's Cognitive Examination, ACE; Frontal Assessment Battery, FAB and Mattis Dementia Rating Scale, MDRS) in 73 Parkinson's disease patients without depression. By receiver operating characteristic curve analysis, these screening instruments were tested against the recently established clinical diagnostic criteria of PDD. Best cut-off score for ACE to identify PDD was 80 points (sensitivity = 74.0%, specificity = 78.1%). For FAB the most optimal cut-off value was 12 points (sensitivity = 66.3%, specificity = 72.2%); whereas for MDRS it was 125 points (sensitivity = 89.8%, specificity = 98.3%). Among the examined test batteries, MDRS had the best clinicometric profile for detecting PDD. Although the types of applied screening instruments might differ from movement disorder clinic to clinic within a country, determination of the most specific and sensitive test for the given population remains to be an important task. Our results demonstrated that the specificity and sensitivity of MDRS was better than those of ACE, FAB and MMSE in Hungary. However, further studies with larger sample size and more uniform criteria for participation are required to determine the most suitable screening instrument for cognitive impairment.
    Parkinsonism & Related Disorders 03/2012; 18(5):553-6. · 3.27 Impact Factor
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    József Janszky, István Balás, Norbert Kovács
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    ABSTRACT: The deep brain stimulation (DBS) is an emerging treatment option in brain disorders in which randomized multicenter trials proved its efficacy leading to licensing different DBS methods in various brain diseases. More recently more and more brain structures have become candidates for being "target" in a possible DBS treatment of epilepsy. At present, only the DBS of the anterior nucleus of the thalamus (ANT) can be considered as a proved method for epilepsy treatment. Other potential targets for DBS treatment in epilepsy are the subthalamic nuclei, and the amygdala-hippocampus complex. There are some ongoing randomized studies to investigating their therapeutical role. The therapeutical outcome of ANT-DBS treatment in drug-resistant epilepsy seems to be better than the new antiepileptic drugs, but much worse than the results of a potential epilepsy surgery. At about 10% of patients may become seizure-free and 50% of patients may have a significant improvement. Nowadays ANT-DBS should be considered as an "ultima ratio" in those adult drug-resistant epilepsy patients with normal intelligence in which neither new antiepileptic drugs nor resective epilepsy surgery are a reasonable therapeutical options.
    Ideggyógyászati szemle 09/2011; 64(9-10):317-20. · 0.35 Impact Factor
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    Movement Disorders 09/2011; 27(1):163-5. · 5.63 Impact Factor
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    ABSTRACT: We investigated adaptive reorganization in Parkinson's disease (PD) by fMRI using a passive movement task and compared the brain activation patterns of 10 patients with left- versus right-sided dominant symptoms. Five healthy controls were also investigated with the same settings. We grouped patients according to the predominant side of symptoms; thus, a right-sided dominant and a left-sided dominant group was formed. The paradigm consisted of a 4-finger passive movement task, which altered with resting states. For each subject, this examination was performed twice: on the left and on the right hand separately. In healthy controls, motor-related areas contralateral to the moving fingers showed activation on fMRI. Concerning PD patients, motor-related areas of the ipsilateral hemisphere - including the primary motor cortex, supplementary motor area, and basal ganglia - seemed to be involved in the motor reorganization in PD. However, we could only demonstrate this reorganization in patients with right-sided dominant symptoms. We suggest that the human brain in PD tries to compensate for the failure of the basal ganglia motor loop by employing alternative (ipsilateral) motor pathways, indicating that a complex reorganization can also take place in disorders like PD which affect the whole motor-related network.
    European Neurology 09/2011; 66(4):220-6. · 1.50 Impact Factor
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    Clinical neurology and neurosurgery 09/2011; 113(9):808-9. · 1.30 Impact Factor
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    21st Meeting of the European Neurological Society; 05/2011
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    ABSTRACT: Deep brain stimulation of the subthalamic nuclei (STN) is a well established treatment in advanced Parkinson's disease (PD). Based on the clinical efficacy and elicited side-effects, both unipolar and bipolar stimulation modes may be applied. Bipolar stimulation usually produces a more focused and therefore thinner area of tissue activated during stimulation than unipolar stimulation does. The primary aim of our clinical study was to quantify the different clinical efficacy between these two stimulation modes. Twenty-one patients with PD previously underwent bilateral STN DBS implantation were involved in the study. Approximately three years after the implantation, we evaluated rigidity, tremor and bradykinesia according to the Unified Parkinson's disease Rating Scale in a practically off condition. Keeping the cathode of the chronic stimulation setting constant, the amplitude of stimulation was changed between 0 and 3.6 V by 0.2 V steps. Subsequently, the improvements in rigidity, tremor and bradykinesia were compared between unipolar and bipolar modes using 60 μs pulse-width and 130 Hz frequency. Within the examined amplitude range, unipolar stimulation usually had a significantly higher efficacy than bipolar stimulation; however, also with a higher rate of side-effects (19% vs. 0%). Depending on the evaluated parkinsonian symptoms, the efficacy of uni- and bipolar stimulation was different. To achieve the same level of improvement during bipolar stimulation, approximately 0.4-0.5 V higher amplitude was required than in unipolar mode. However in some cases, the efficacy of bipolar stimulation was unable the reach that of unipolar stimulation within the examined amplitude range.
    Parkinsonism & Related Disorders 01/2011; 17(1):50-4. · 3.27 Impact Factor
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    ABSTRACT: Bilateral deep brain stimulation of the subthalamic nuclei (STN) is a well-established and cost-effective treatment in advanced PD. To quantitatively analyze the change in use of antiparkinsonian drugs one year after subthalamic deep brain stimulator (DBS) implantation in patients with idiopathic Parkinson's disease (PD). Eighteen consecutive patients with advanced PD underwent bilateral STN DBS implantation were involved in the study. The stimulation achieved a stable and clear clinical benefit in all of the cases. One year after the implantation, drug usage of patients was analyzed and correlated with the postoperative symptomatic improvement measured by the modified Hoehn-Yahr, Schwab and England, and Unified Parkinson's Disease Rating Scales. Because none of the investigated variables followed the normal distribution, non-parametric Wilcoxon signed-rank, McNemar and Kendell's T tests were applied. Preoperatively, the patients used 12.05 +/- 4.57 tablets a day out of 3.19 +/- 0.97 different antiparkinsonian drugs, which was significantly reduced by deep brain stimulation to the application of 7.00 +/- 2.96 tablets out of 1-3 (1.84 +/- 0.76) drugs (p < 0.001). Meanwhile, the usage of amantadine, MAO-B and COMT inhibitors was also significantly decreased (p < 0.05). The dosage of dopaminerg medication was significantly lowered from 1136 mg to 706 mg expressed in levodopa equivalent dosage (p < 0.001) whereas the UPDRS-III also improved by 48.6%. Our study is in accordance with previously published international findings that antiparkinsonian medication can be significantly lowered after bilateral STN DBS. Because not only the dosage, but also the applied number of tablets were decreased, it may have resulted in a better compliance and quality of life.
    Ideggyógyászati szemle 09/2010; 63(9-10):314-9. · 0.35 Impact Factor
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    Movement Disorders 06/2009; 24(10):1556-7. · 5.63 Impact Factor
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    ABSTRACT: ObjectiveThe cause or the physiological role of déjà vu (DV) in healthy people is unknown. The pathophysiology of DV-type epileptic aura is also unresolved. Here we describe a 22-year-old woman treated with deep brain stimulation (DBS) of the left internal globus pallidus for hemidystonia. At certain stimulation settings, DBS elicited reproducible episodes of DV.MethodsNeuropsychological tests and single-photon-emission computed tomography (SPECT) were performed during DBS-evoked DV and during normal DBS stimulation without DV.ResultsSPECT during DBS-evoked DV revealed hyperperfusion of the right (contralateral to the electrode) hippocampus and other limbic structures. Neuropsychological examinations performed during several evoked DV episodes revealed disturbances in nonverbal memory.ConclusionOur results confirm the role of mesiotemporal structures in the pathogenesis of DV. We hypothesize that individual neuroanatomy and disturbances in gamma oscillations or in the dopaminergic system played a role in DBS-elicited DV in our patient.
    Epilepsy & Behavior 01/2009; · 2.06 Impact Factor
  • Parkinsonism & Related Disorders 01/2009; 15. · 3.27 Impact Factor
  • Parkinsonism & Related Disorders 01/2009; 15. · 3.27 Impact Factor
  • Parkinsonism & Related Disorders 01/2009; 15. · 3.27 Impact Factor
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    ABSTRACT: Although there is a relatively high prevalence of both idiopathic Parkinson's disease (PD) and epilepsy in the elderly population, and PD occurs more frequently in people with epilepsy, there are no studies investigating the efficacy and tolerability of antiepileptic drugs (AEDs) in people with PD. We describe the case of a 71-year-old man with PD who experienced several seizures. The initiation of antiepileptic treatment with oxcarbazepine (OXC) provoked a severe, long-lasting psychotic state. The patient had previously experienced similar psychotic episodes during dopamine agonist therapy. Because recent animal studies have proven that OXC and its active metabolite exert important dopamine- and serotonin-promoting effects in the limbic area, we assumed that in our case the OXC-induced psychosis was mediated by the dopaminergic system. We concluded that OXC should be used with care in cases of a constellation of PD and epilepsy because of its possible psychiatric side effects. The dopaminergic effect of OXC and its active metabolite might also play an ambivalent, but important role in the treatment of alcohol addiction and bipolar disorder; therefore, further studies are required to investigate its psychopharmacological aspects.
    Epilepsy & Behavior 05/2008; 12(3):492-3. · 2.06 Impact Factor
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    ABSTRACT: The analysis of long-latency event-related potentials (ERPs) is of importance in the evaluation of certain cognitive functions and in following their subsequent changes. The aim of the present study was to investigate whether deep brain stimulation (DBS) itself can cause changes in the configuration of the ERPs. Using a standard oddball auditory paradigm, we elicited auditory cognitive ERPs in 23 Parkinson's disease patients (in both DBS-ON and DBS-OFF conditions) and in 14 healthy controls. The P200 and P300 amplitudes and latencies, the motor reaction times and the accuracy of button pressing were compared between the DBS-ON and DBS-OFF states and subsequently correlated with the applied stimulation voltage and disease duration. Comparison of the DBS-ON and DBS-OFF conditions revealed that neither the amplitude nor the latency of the examined ERP components changed significantly. However, the behavioral and attentional aspects (e.g. the accuracy of the button pressing responses to the target signal) definitely improved after the DBS was turned on. Positive correlations were demonstrated between the P300 amplitudes over the central and frontal regions and the optimal stimulation voltage and between the disease duration and P300 latencies over the Cz and Fz sites. In conclusion, our data indicate that DBS may have different impacts on various electrophysiological parameters during the oddball paradigm.
    Parkinsonism & Related Disorders 03/2008; 14(6):476-80. · 3.27 Impact Factor