[Show abstract][Hide abstract] ABSTRACT: Antiepileptic drugs are generally used to control the cortical hyperexcitable states. But some of them are also effective on the peripheral nervous system, so they may be used in some states like neuropathic pain. Several recent reports suggest the possible effects of antiepileptic drugs on peripheral nerve excitability. Strength duration time properties gives an indirect idea about the persistent, paranodal sodium (Na) channels and may indirectly reflect the peripheral nerve excitability. Topiramate suppresses the cortical hyperexcitability, but previous studies could not prove a significant effect of topiramate on peripheral nerves. The aim of this study is to investigate the probable nerve excitability changes caused by topiramate.
Forty migraine patients and 40 controls were included in the study. Median motor and sensory conduction parameters were recorded. Strength duration properties were also recorded from abductor pollicis longus muscle, with the stimulation of median nerve. The electrophysiological studies were repeated 4 weeks after the initiation of topiramate in the treatment group.
Nerve conduction parameters were not significantly affected by 4-week topiramate treatment. But the strength duration time constant decreased significantly, reflecting a reduction in the excitability. This decrement seemed to be more obvious in those in whom topiramate was also clinically useful.
The method used demonstrated a probable effect of topiramate on the peripheral nerve excitability.
Journal of clinical neurophysiology: official publication of the American Electroencephalographic Society 06/2012; 29(3):268-70. · 1.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A 48-year-old man presented with left ptosis and double vision. Laboratory test findings indicated acute lymphoblastic leukemia (ALL). Lymphoblastic infiltration of both cavernous sinuses was observed on pituitary gland magnetic resonance imaging. Leukemias may present by many clinical conditions, but isolated cranial nerve palsy is very rare. To our knowledge, this is the first case of ALL presenting with oculomotor nerve palsy. Clinicians should consider oculomotor nerve palsy as the first ALL indication.
[Show abstract][Hide abstract] ABSTRACT: Although it is well known that ES alters cortical excitability, little is known about the relationship between ES outcome and cortical excitability. Transcranial magnetic stimulation has been successfully used to evaluate cortical excitability in epilepsy patients. The present study aimed to assess the value of the motor threshold (MT) and cortical silent period (CSP) as predictors of the outcome of temporal lobe epilepsy surgery (TLES).
Epileptic foci in the epilepsy patients were identified via video-electroencephalography (v-EEG) monitoring, brain magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET), and neurophysiological testing. MT, CSP-150, and CSP-max were measured in 10 epilepsy patients on both the ipsilateral and contralateral side of the epileptic focus 1 week before and 3 months after TLES. Pre- and post-operative MT and CSP measurements were compared, and the results were interpreted based on the clinical outcome of TLES.
Mean follow-up period was 28.8 months. In all, 8 patients were seizure-free post TLES, whereas in 2 patients seizures persisted. No significant differences were observed in ipsilateral or contralateral hemisphere MT measurements before and after surgery. Both CSP-150 and CSP-max values in the non-focal hemispheres decreased in the 8 patients that were seizure-free post TLES, whereas no differences were observed in the 2 patients with seizures that persisted post TLES.
The present findings indicate that monitoring pre- and post-TLES CSP changes may be predictive of the early clinical outcome of TLES.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate cutaneous-silent-period (CSP) parameters in patients with restless legs syndrome (RLS) and examine the effects of treatment on CSP which, to our knowledge, have not been investigated till date.
A total of 25 patients with RLS and 25 healthy volunteers were studied. CSP latency and duration in the upper and lower extremities were examined in the two groups. In RLS patients, the variables were examined before and after pramipexole treatment.
Lower-extremity CSP latency was longer (106.22±11.69 ms vs. 91.67±8.53 ms; p<0.001) and CSP duration was shorter (35.50±10.91 ms vs. 49.47±6.43 ms; p<0.001) in patients, compared with controls. In the patient group, CSP durations in the upper (40.88±7.95 ms vs. 46.84±10.22 ms; p=0.006) and lower extremities (35.50±10.91 ms vs. 44.91±6.43 ms; p=0.005) were prolonged after treatment, compared with pre-treatment values.
Small-fibre neuropathy may exist in RLS. In addition, we suggest that pramipexole may regulate cortical and spinal inhibitory mechanisms.
The use of CSP may aid in the diagnosis of RLS and may be used as a measure of treatment effectiveness.
Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 07/2011; 123(1):154-9. · 3.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Vasomotor reactivity, which can be defined as the cerebral vasculature response to hypoxia, is not well known in epilepsy patients. We aimed to evaluate cerebrovascular reserve in idiopathic generalized epilepsy patients using transcranial Doppler ultrasonography (TCD). The study included 20 patients and 20 healthy volunteers. Diagnosis of epilepsy was based on the observation of seizure in the video electroencephalography unit. Cerebrovascular reactivity was evaluated by means of the breath-holding index. Insonation depth and basal velocity were symmetrical and not significantly different between the two groups (p[0.05). The breath-holding index ranged from 0.62 to 4.45 (mean 2.13 +/- 0.83) in the epilepsy patients and 0.57 to 2.55 (mean 1.60 +/- 0.46) in the control group (p\0.05). Breath-holding index values showed that cerebrovascular reserve in epilepsy patients was increased, as compared to healthy individuals. Cerebrovascular reserve was increased in epilepsy patients; this should not be accepted as an abnormality, but might have been the result of an adaptive mechanism that protects the brain from hypoxic challenges due to seizure apnea.
Journal of Neurology 05/2010; 257(5):833-8. · 3.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cerebrovascular blood flow in absence seizures and flow patterns during the ictal period have not been thoroughly investigated. We aimed to evaluate cerebral blood flow changes in typical juvenile absence seizures during the ictal and postictal phases. Seizures were recorded in three patients (mean age: 21 +/- 1 years) with multiple daily typical absence seizures. Simultaneous video electroencephalography and bilateral middle cerebral artery transcranial Doppler ultrasonography recordings were conducted during seizures. Basal, ictal, and postictal blood flow velocities were recorded bilaterally, and offline analyses were performed in relation with generalized spike and wave discharges. Total of 43 seizures were recorded. Ictal increase and postictal decrease of cerebral blood flow velocities were significant for both sides (P < 0.001). The interhemispheric asymmetry in the ictal velocity increase was significant (P < 0.05). The interhemispheric asymmetry in the postictal velocity decrease was not significant (P > 0.05). The blood flow velocity increase after seizure onset indicates a vascular coupling mechanism. A sudden and then a gradual decrease in blood flow velocity, which lasted even after the seizure ceased, might suggest a preventive mechanism to avoid excessive seizure duration or even an absence status epilepticus. Significant asymmetries in increase and a symmetrical decrease may support the cortical focus theory.
Journal of Neurology 02/2010; 257(7):1181-7. · 3.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Carrying a heavy backpack exerts compression on shoulders with the potential to cause brachial plexopathy. Upper extremity numbness, weakness and atrophy associated with the use of a heavy backpack have been reported previously and termed as pack palsy or rucksack paralysis. We evaluated clinical and electrophysiological characteristics of 5 patients with backpack palsy. Up to our knowledge neurophysiological findings in patients with backpack palsy have not been examined in detail earlier. Gradually progressing paresthesias, numbness and weakness of the upper extremity were typical symptoms and were appeared just after carrying a heavy backpack during longtime marching. Electrophysiologically all cases showed posterior cord lesion and lateral cord lesion was added to the clinical picture in one. Resting was recommended to the patients. Clinical and electrophysiological full recovery observed after six months. Frequently observed posterior cord lesions are thought to be caused by microtraumas and tractions that are exerted on shoulders and axillar region, depending on heaviness of the pack and style of carrying
[Show abstract][Hide abstract] ABSTRACT: Some recent studies indicated that administration of antiepileptic drugs (AEDs) is associated with occlusive vascular diseases. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide (NO) synthase inhibitor and increased plasma ADMA levels are associated with cardiovascular morbidity. We hypothesized that elevated plasma ADMA concentrations exist in patients receiving AEDs and administration of AEDs may result in an increased risk of occlusive vascular disease. Thirty five newly diagnosed epilepsy patients participated, patients were classified into two groups according to their antiepileptic drug regimen. In the first group patients were treated with valproic acid (VPA, n=17) (500-1500 mg/day), and in the second group with carbamazepine (CBZ, n=18) (400-1200 mg/day). ADMA levels significantly increased after treatment in both VPA (p=0.002) and CBZ (p=0.024) groups. Homocysteine levels increased in both groups, but the difference was significant only in VPA group (p=0.005). Serum folate levels did not differ in VPA group, but significantly decreased in CBZ group (p=0.006). Vitamin B(12) levels significantly increased in VPA group (p=0.001) but did not differ in CBZ group. Correlation analysis showed that the increases in ADMA and homocysteine levels in the VPA group were higher however the differences between the groups were insignificant. The correlations of the changes between ADMA and other parameters were all insignificant in both VPA and CBZ groups. In conclusion our data suggest that elevated ADMA levels may be responsible for the increased cardiovascular risk in patients with epilepsy under AED therapy.
Epilepsy research 09/2009; 87(1):54-8. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Antiepileptic and neuroprotective effects of melatonin (N-acetyl-5-methoxytryptamine) have been shown at higher doses (50-160 mg/kg). We aimed to investigate the antiepileptic effects of low-dose melatonin (10 mg/kg) on pentylenetetrazol (PTZ)-induced experimental epilepsy model.
Twelve male albino guinea pigs weighing 500-800 g were used in our work. Initially, latent period, seizure intensity and mortality parameters were evaluated during the epileptic seizure induced by PTZ. After a recovery period of 7 days, effects of the neuroprotective agent, melatonin (which is dissolved in 2.5% ethanol-saline solution), on epileptic seizures induced by PTZ were evaluated. Effects of 2.5% ethanol, which is an anticonvulsant agent when administered acutely in high concentrations, on PTZ-induced seizures were also evaluated.
Data obtained from the study groups (PTZ, PTZ + melatonin and PTZ + ethanol) were evaluated by paired t-test, and p<0.005 was considered statistically significant. The differences of latent periods between the PTZ and PTZ + melatonin groups were found to be statistically significant (p<0.001).
Although melatonin does not have a primary anticonvulsant effect at low doses (10 mg/kg), it lowers the mortality rates and attenuates seizure severity while increasing the latent period.
Neurological Research 02/2009; 31(9):989-95. · 1.45 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Maternal use of antiepileptic drugs (AEDs) during pregnancy has been associated with an increased risk of congenital abnormalities in the fetus. This is partly attributable to AEDs. We aimed to analyse seizure frequency and the rate and type of any congenital malformation related to pregnancies in women with epilepsy in this prospective study. Eighty four pregnant women with epilepsy on AEDs were followed for congenital malformations. Z test was used for statistical analysis. Pregnancy did not influence the seizure frequency in 64 (76.2%) pregnancies. The seizure frequency increased in 16 (19.04%) pregnancies. In 4 (4.76%) pregnancies the number of seizures decreased during pregnancy. Overall percentage of congenital malformations in infants of mothers with epilepsy treated with AEDs was 10%, versus 3.65% in the general Turkish population. Percentages of malformations in children of pregnancies in women with epilepsy on antiepileptic drugs (AEDs) were; 6.52% (3/46) for carbamazepine (CBZ), 14.28% (2/14) for phenytoin (PHT), 13.33% (2/15)for valproic acid (VPA) and 20% (1/5) for phenobarbital (PB). This comfirms previous reports that all four AEDs (CBZ, PHT VPA, PB) are associated with an increased risk of congenital malformations, although CBZ seems to be the the safest agent in monotherapy.