Clinical Neuroscience

[Non-invasive brain stimulation for relieving acute and chronic pain]


MAY 30, 2012

Clinical Neuroscience - 2012;65(05-06)

[Controlling pain has always been one of the biggest challenges of medical science. Despite pharmacological developments, still many patients suffer from long-lasting pain. During the last 40 years several surgical interventions have been used to modulate the activity of the central nervous system in order to control chronic, pharmacoresistant pain. Because such interventions may involve very serious adverse events, safer and at least equally efficient methods are still required. In the 90’s new techniques of non-invasive brain stimulation have been introduced that enable the facilitation or inhibition of distinct cortical areas. These methods are based on the electrical stimulation of brain structures and to date they have been successfully used to modulate perceptual, cognitive and motor functions in healthy subjects and various diseases as well. In this review we describe such techniques of non-invasive brain stimulation, namely repeated transcranial magnetic stimulation and transcranial direct current stimulation and review the current literature about their efficacy in controlling acute and chronic pain.]



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Clinical Neuroscience

[Effect of two month positive airway pressure therapy on the structure of sleep, cognitive function and anxiety]


[Obstructive sleep apnea is a common disorder, characterized by repeated episodes of upper airway obstruction during sleep, resulting intermittent hypoxia and disruption of the normal sleep pattern, which caused cognitive dysfunction in these patients. Nasal continuous positive airway pressure is the treatment of choice for this disorder. The aim of the study is to evaluate the effect of short-term positive airway pressure on sleep pattern (polisomnographic measures), cognitive function and anxiety. Twenty four newly diagnosed and previously untreated patients with obstructive sleep apnea were evaluated a battery of neuropsychological tests before and after 2 and a half months of the treatment. We focused on working memory, short and long-term episodic memory, executive functions, anxiety and subjective sleepiness. Our results showed that the two and half month of treatment improved the respiration during sleep, sleep pattern and the subjective sleepiness. We found improvement in short- and long-term verbal memory, and complex working memory. Despite of treatment we did not find improvement in visuospatial learning. These results reveal that 2 and a half months of positive airway pressure treatment restored not only the normal respiration during sleep and normal sleep pattern, but also the cognitive functions. Our study suggests that cognitive dysfunction is at least partial reversible in obstructive sleep apnea patients after positive airway pressure treatment.]

Clinical Neuroscience

[Prognostic factors of primary spinal tumors]

LAZÁRY Áron, BORS István Béla, SZÖVÉRFI Zsolt, RÓNAI Márton, VARGA Péter Pál

[Aims - Primary spinal tumors are rare diseases and there are less objective data in the international literature. We analyzed the epidemiology and clinical consequences of primary spinal tumors based on the clinical experience of the National Center for Spinal Disorders. Methods - Demographic and clinical data of 300 patients treated in our institute between 1995 and 2007 was collected retrospectively and analysed. Results - Beyond the relatively more frequent pathologies (chordoma, myeloma multiplex) we treated in our hospital some of the very rare types of tumors (spinal leiomyosarcoma, synovial sarcoma). Primary spinal tumors are most often located in the lumbosacral region causing most frequently (73%) local or radiating pain. Modern therapy of these patologies is based on the surgical intervention. Mean operation time was 130 minutes, mean blood loss was 650 ml in our pratice during these often technically challenging surgeries. We found a significant association among the operation time, the blood loss and the extension of the tumor (p<0.01). Histology (p<0.0001), severity of symptomes (p<0.05) and blood loss (p<0.05) were significantly related to mortality. Local recurrence was more than 5-fold in case of patients previously operated in another institute (p<0.0001). Conclusions - We successfully determined some significant prognostic factor on clinical behavior of primary spinal tumors performing a large scale retrospective study. Long time follow up of the patients and completion of our database with prospective data are planned for the future.]

Clinical Neuroscience

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Clinical Neuroscience

[Acute and chronic stress induced changes in gene transcriptions related to Alzheimer’s disease]

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[Preclinical and clinical studies demonstrate that stress may be implicated in the risk of neurodegenerative diseases such as Alzheimer’s disease (AD). Our study aimed to investigate the effects of acute and chronic immobilization stress (IS) on the gene transcriptions of β-actin, amyloid precursor protein (APP) and mitogen activated protein kinase-1 (MAPK-1), proteins related to synaptic plasticity and neuronal degeneration. Male Wistar rats were exposed to IS for five hours daily for 3 days (acute stress) or through 7-14-21 days (chronic stress). At the end of exposure periods, total RNA was purified from the cortex and hippocampus. The amounts of β-actin, APP and MAPK-1 mRNA were determined with real time PCR method. Our results indicate that the mRNA expression of β-actin and APP followed a U-shaped time-response curve. Both acute and chronic IS caused a significant increase in β-actin and MAPK-1 mRNA expression. Significant APP mRNA elevation was observed only by the 3rd week after RS. Our findings demonstrate that both acute and chronic IS lead to gene transcriptional changes of β-actin, APP and MAPK-1. These proteins maintain the normal function of the cytoskeleton and the synaptic plasticity. The above changes may lead to cognitive deterioration, and the development of AD.]

Clinical Neuroscience

[European treatment recommendation of neuromyelitis optica spectrum disorders: critical remarks and case discussion]


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Clinical Neuroscience

The effects of 30 Hz, 50 Hz AND 100 Hz continuous theta burst stimulation via transcranial magnetic stimulation on the electrophysiological parameters in healthy individuals

OZDEMIR Zeynep, ACAR Erkan, SOYSAL Aysun

Transcranial magnetic stimulation is a non-invasive procedure that uses robust magnetic fields to create an electrical current in the cerebral cortex. Dual stimulation consists of administering subthre­shold conditioning stimulation (CS), then suprathreshold test stimulation (TS). When the interstimulus interval (ISI) is 1-6 msec, the motor evoked potential (MEP) decreases in amplitude; this decrease is termed “short interval intracortical inhibition” (SICI); when the ISI is 7-30 msec, an increase in MEP amplitude occurs, termed “short interval intracortical facilitation” (SICF). Continuous theta burst stimulation (cTBS), often applied at a frequency of 50 Hz, has been shown to decrease cortical excitability. The primary objective is to determine which duration of cTBS achieves better inhibition or excitation. The secondary objective is to compare 50 Hz cTBS to 30 Hz and 100 Hz cTBS. The resting motor threshold (rMT), MEP, SICI, and SICF were studied in 30 healthy volunteers. CS and TS were administered at 80%-120% and 70%-140% of rMT at 2 and 3-millisecond (msec) intervals for SICI, and 10- and 12-msec intervals for SICF. Ten individuals in each group received 30, 50, or 100 Hz, followed by administration of rMT, MT-MEP, SICI, SICF immediately and at 30 minutes. Greater inhibition was achieved with 3 msec than 2 msec in SICI, whereas better facilitation occurred at 12 msec than 10 msec in SICF. At 30 Hz, cTBS augmented inhibition and suppressed facilitation, while 50 Hz yielded less inhibition and greater inter-individual variability. At 100 Hz, cTBS provided slight facilitation in MEP amplitudes with less interindividual variability. SICI and SICF did not differ significantly between 50 Hz and 100 Hz cTBS. Our results suggest that performing SICI and SICF for 3 and 12 msec, respectively, and CS and TS at 80%-120% of rMT, demonstrate safer inhibition and facilitation. Recently, TBS has been used in the treatment of various neurological diseases, and we recommend preferentially 30 Hz over 50 Hz cTBS for better inhibition with greater safety and less inter-individual variability.

Clinical Neuroscience

[The role of transcranial magnetic stimulation in clinical diagnosis: motor evoked potential (MEP)]

ARÁNYI Zsuzsanna, SIMÓ Magdolna

[Transcranial magnetic stimulation allows painless, non-invasive stimulation, neurophysiological evaluation of nervous structure covered by bone or difficult to access for other reasons. In the clinical setting the technique is mainly used for the investigation of the corticospinal tract (motor evoked potential: MEP). Based upon our experience with patients examined over the course of four years, we have attempted to highlight the clinical situations, where diagnostic help is provided by this technique. MEP in general has proved to be a sensitive and reliable examination. Its significance is apparent mainly in situations where clinical signs of corticospinal tract dysfunction are not evident, or they are masked by lower motoneurone involvement, and where neuroimaging techniques are not informative. The demonstration of subclinical corticospinal lesion is often essential to establish the diagnosis in multiple sclerosis and amyotrophic lateral sclerosis. The technique however received little attention so far with respect to its role in the diagnosis of various spinal cord disorders, and in the demonstration of intact corticospinal function in case of weakness, psychogenic in origin. We have endeavoured to provide further evidence in support of this, and thereby advocating a wider clinical application of the technique.]

Clinical Oncology

[New aspects in cancer pain relief]


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Clinical Neuroscience

[The role of transcranial magnetic stimulation in clinical diagnosis: facial nerve neurography]

ARÁNYI Zsuzsanna, SIMÓ Magdolna

[Facial nerve neurography involving magnetic stimulation techniques can be used to assess the intracranial segment of the facial nerve and the entire facial motor pathway, as opposed to the traditional neurography, involving only extracranial electric stimulation of the nerve. Both our own experience and data published in the literature underline the value of the method in localising facial nerve dysfunction and its role in clinical diagnosis. It is non-invasive and easy to perform. Canalicular hypoexcitability has proved to be the most useful and sensitive parameter, which indicates the dysfunction of the nerve between the brain stem and the facial canal. This is an electrophysiological finding which offers for the first time positive criteria for the diagnosis of Bell’s palsy. The absence of canalicular hypoexcitability practically excludes the possibility of Bell’s palsy. The technique is also able to demonstrate subclinical dysfunction of the nerve, which can be of considerable help in the etiological diagnosis of facial palsies. For example, in a situation where clinically unilateral facial weakness is observed, but facial nerve neurography demonstrates bilateral involvement, etiologies other than Bell’s palsy are more likely, such as Lyme’s disease, Guillain-Barré syndrome, meningeal affections etc. Furthermore, the technique differentiates reliably between peripheral facial nerve lesion involving the segment in the brain stem or the segment after leaving the brainstem.]


[Pain relief in metastatic bone disease]

BOÉR Katalin

[Metastatic bone disease is a hallmark of distant relapse of a number of solid tumours. The treatment of bone metastases is palliative, the main goal is to relieve pain, whereas it’s also important to reduce the risk of bone fractures, prolong survival and maintain the physical activity of patients. Pain is one of the most common symptoms of bone metastases, and state-of-the-art pain relief has an important role in maintaining the patients’ quality of life. Therapies to control pain include drug therapy, radiotherapy, surgery, systemic oncotherapy, such as chemotherapy and/or hormone therapy, multibone radioisotope therapy and administration of bisphosphonates. Regarding the relief of pain caused by malignant tumours, the guidelines developed by the World Health Organization should be followed. The algorithm of pain relief starts with assessment of the pain’s intensity and includes both pharmacological and nonpharmacological interventions. Analgesics used for pain relief include nonopioids, opioids and adjuvant agents. The pain can be efficiently relieved with the combined use of modern analgesics in the great majority of patients.]