Effects of spinal cord stimulation on heart rate variability in patients with chronic pain.

BACKGROUND: 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). RESULTS: 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. CONCLUSION: 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.

Secondarily generalized seizures in temporal lobe epilepsy.

PURPOSE: Secondarily generalized tonic-clonic seizure (SGTCS) may occur rarely in temporal lobe epilepsy (TLE), but SGTCS is the major risk factor for sudden death and for seizure-related fatal injuries. Our aim was to investigate clinical factors associated with the occurrence of SGTCS in TLE by addressing two questions: (1) What clinical features differentiate patients with TLE who regularly had SGTCS from those who did not? (2) Is there an association of secondarily generalized seizures with preceding seizure elements and clinical data? METHODS: We included 171 patients with TLE (mean age 34.4 ± 10) who participated in our presurgical evaluation program, which included continuous video-electroencephalography (EEG) and magnetic resonance imaging (MRI). Patients had a temporal lobectomy as a result of mesial or neocortical TLE. To reevaluate the archived seizures, we selected the consecutively recorded seizures of each patient. If the patient had more than three recorded seizures, then we reevaluated only the first three. Altogether video-recorded seizures of 402 patients were reanalyzed. KEY FINDINGS: A positive association between the presence of hippocampal sclerosis on the MRI and SGTCS in the patient history was found, whereas ictal speech and pedal automatism showed a negative association with a SGTCS history. The age of patients showed a positive association, whereas patient's reactivity before and during the seizure, oral/pedal automatisms, and vocalizations showed a negative association with secondary generalization of a focal-onset seizure during video-EEG monitoring. SIGNIFICANCE: Clinical features associated with SGTCS may help clinicians during presurgical monitoring identify high-risk patients for SGTCS. Our study may help in understanding the pathophysiology of secondary generalization.

Reorganization of motor system in Parkinson's disease.

BACKGROUND/AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Does obstetric brachial plexus injury influence speech dominance?

OBJECTIVE: Right-handedness and left-sided language lateralization is an unresolved mystery with unknown cause/effect relations. Most studies suggest that the language lateralization is related to a fundamental brain asymmetry: right-handedness may be secondary. We analyzed the possibility of an opposite cause/effect relation: whether asymmetric hand usage (as a cause) can influence language lateralization (as a consequence). METHODS: We determined language lateralization by functional magnetic resonance imaging in 15 subjects whose upper limb (UL) had been injured at birth because of unilateral damage of the brachial plexus. These subjects were able to use only one (the noninjured) UL perfectly. RESULTS: We found correlation between the severity of right-sided UL injuries and hand usage dysfunction and the degree of left-to-right shift of language lateralization. There was, however, not a complete switch of language lateralization. INTERPRETATION: Right-sided UL injury can induce a left-to-right shift in language lateralization, suggesting that hand usage can influence language lateralization. These findings may contradict the broadly accepted theory that right-handedness is a secondary phenomenon caused by left-sided hemispheric language lateralization. However, the cause/effect problem between asymmetric hand usage and language lateralization is not resolved in this study. Our findings may support the theory that gestures had a crucial role in human language evolution and is a part of the language system even today.

[Brain lateralization and seizure semiology: ictal clinical lateralizing signs]. / Agyi lateralizáció és az epilepsziás rohamok tünettana: ictalis klinikai lateralizációs jelek.

Clinical lateralizing signs are the phenomena which can unequivocally refer to the hemispheric onset of epileptic seizures. They can improve the localization of epileptogenic zone during presurgical evaluation, moreover, their presence can predict a success of surgical treatment. Primary sensory phenomena such as visual aura in one half of the field of vision or unilateral ictal somatosensory sensation always appear on the contralateral to the focus. Periictal unilateral headache, although it is an infrequent symptom, is usually an ipsilateral sign. Primary motor phenomena like epileptic clonic, tonic movements, the version of head ubiquitously appear contralateral to the epileptogenic zone. Very useful lateralization sign is the ictal hand-dystonia which lateralizes to the contralateral hemisphere in nearly 100%. The last clonus of the secondarily generalized tonic-clonic seizure lateralizes to the ipsilateral hemisphere in 85%. The fast component of ictal nystagmus appears in nearly 100% on the contralateral side of the epileptic focus. Vegetative symptoms during seizures arising from temporal lobe such as spitting, nausea, vomiting, urinary urge are typical for seizures originating from non-dominant (right) hemisphere. Ictal pallor and cold shivers are dominant hemispheric lateralization signs. Postictal unilateral nose wiping refers to the ipsilateral hemispheric focus compared to the wiping hand. Ictal or postictal aphasia refers to seizure arising from dominant hemisphere. Intelligable speech during complex partial seizures appears in non-dominant seizures. Automatism with preserved consciousness refers to the seizures of non-dominant temporal lobe.

[Effect of epileptic seizures on the heart rate]. / Az epilepsziás rohamok hatása a szívfrekvenciára.

BACKGROUND: Sudden death appears in 8-17% of epilepsy patients non-responding to antiepileptic therapy. Some studies suggest that the most common cause of death is seizure-related cardiac arrhythmia. AIM OF STUDY: To analyze the alteration of the heart rate six hours before and after the seizures. METHODS: Eighteen patients suffering from focal epilepsy were examined before epilepsy surgery. Video-EEG-ECG was carried out for 2-10 days, and 32 seizures were registered. Analysis of the heart rate was based on the 5-minute-long epochs of the ECGs taken at the 5-10-15-30th minutes and at the 1-3-6th hours before and after seizures. RESULTS: The heart rate increases (from an average of 69 beats/min to 92 beats/min, p<0.001) immediately after seizures, though significantly higher heart rate was observed 3 hours after seizures. There were no patients with severe peri-ictal bradycardia. In one of our patients, ectopic cardiac rhythm occurred after a generalized tonic-clonic seizure. CONCLUSIONS: We can conclude that the sympathetic activity increases while the parasympathetic activity decreases after seizures. The observed alterations lasted for a long time and predict fatal arrhythmias. These suggest that sudden death in epilepsy can be induced by cardiac arrhythmias connected with epileptic seizures.

Coffee consumption may influence hippocampal volume in young women.

Caffeine is the most often used psychoactive substance. Caffeine may influence neuroplasticity in animals. We investigated the relationship between caffeine intake (coffee consumption) and brain morphology. Forty-five healthy, non-smoking women aged 19-30 were included in the present study. We used semi-automatic user-independent MR volumetry and voxel-based morphometry. We investigated the relationship between caffeine intake (coffee consumption) and the volumes of the cortical brain structures where caffeine is supposed to act. We found that high-level and low-level caffeine intake was associated with a larger hippocampus compared to moderate-level caffeine intake. The other brain structures showed no association with coffee consumption or caffeine intake. The U-shape association between caffeine concentration and its effect has already been described in some experimental studies. To our knowledge this is one of the very first studies, which tries to find an association between brain morphology and coffee consumption or caffeine intake in humans using MR imaging.