Mehmet Yücel

P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?

Tascilar ME, Turkkahraman D, Oz O, Yucel M, Taskesen M, Eker I, Abaci A, Dundaroz R, Ulas UH. P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?

Effect of pramipexole on cutaneous-silent-period parameters in patients with restless legs syndrome

OBJECTIVE 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. METHODS 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. RESULTS 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. CONCLUSIONS Small-fibre neuropathy may exist in RLS. In addition, we suggest that pramipexole may regulate cortical and spinal inhibitory mechanisms. SIGNIFICANCE The use of CSP may aid in the diagnosis of RLS and may be used as a measure of treatment effectiveness.

Cutaneous silent period changes in Type 2 diabetes mellitus patients with small fiber neuropathy.

OBJECTIVE Small myelinated (A-delta) and unmyelinated (C) somatic sensory fibers are initially affected and may be the earliest exhibited sign of neuropathy in glucose dysmetabolism. Cutaneous silent period (CSP) is an inhibitory spinal reflex and its afferents consist of A-delta nerve fibers. The aim of this study was to evaluate CSP changes in Type 2 diabetic patients with small fiber neuropathy. METHODS Forty-three patients and 41 healthy volunteers were included. CSP latency and duration, as well as CSP latency difference of the upper and lower extremities, were examined. RESULTS Nerve conduction studies were within normal limits in both groups. Lower extremity CSP latency was longer (122.1+/-15.5 vs. 96.4+/-6.4 ms; p<0.001), CSP duration was shorter (29.5+/-8.9 vs. 43.1+/-5.0 ms; p<0.001), and latency difference was longer (48.1+/-12.6 vs. 22.7+/-3.7; p<0.001) in patients than controls. The difference was more significant in patients with neuropathic pain. No significant difference existed in upper extremity on CSP evaluation. CONCLUSION The CSP evaluation together with nerve conduction study, has been demonstrated to be beneficial and performance of latency difference in addition to CSP latency and duration may be a valuable parameter in electrophysiological assessment of diabetic patients with small fiber neuropathy. SIGNIFICANCE An additional CSP evaluation may be considered in cases which nerve conduction studies do not provide sufficient information.

Effects of topiramate on peripheral nerve excitability.

Purpose: 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. Methods: 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. Results: 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. Conclusions: The method used demonstrated a probable effect of topiramate on the peripheral nerve excitability.

P50 sensory gating in children and adolescents with ADHD and effects of methylphenidate administration on P50 sensory gating / Dikkat eksikliği hiperaktivite bozukluğu tanılı çocuk ve ergenlerde P50 duyusal kapılama ve metilfenidat tedavisinin P50 duyusal kapılama üzerine etkisi

Objective: The P50 is thought to resect a sensory gating mechanism and prevent information overload in humans. Failure to inhibit the P50 auditory event evoked response can occur in attention deficit hyperactivity disorder (ADHD) patients. The aims of the present study were to examine the inhibition of the P50 auditory event evoked potential and the effects of methyphenidate administration on P50 parameters in children and adolescents diagnosed with ADHD. Methods: Twenty-two drug-free subjects, aged 9-14, who were diagnosed with ADHD (the combined type) according to the DSM-IV criteria, and 18 mentally and physically healthy subjects, aged 9-12, were included in the study. First, P50 parameters were measured in drug-free ADHD subjects and healthy controls. Following this measurement, 10 mg of methylphenidate was administered to the ADHD group. The P50 measurement was repeated 1 hour following methylphenidate administration in the ADHD subjects. The healthy control group was not re-examined. Results: A significant difference was found in P50 test latency, test amplitude, and P50 ratio values between the ADHD group and healthy controls. Significant differences were also found in conditioning latency, test latency, test amplitude, and P50 ratio values between before and after methyphenidate administration in the ADHD group. Conclusions: The results of the present study point out an association between P50 and ADHD and they also show that methyphenidate administration increases the P50 suppression level. Since, this is the first study evaluating sensory gating in children and adolescents with ADHD, it should be considered as a preliminary study. Further studies with large study samples are warranted.

Nerve excitability properties in early preclinical diabetic neuropathy

Diabetic polyneuropathy can be easily diagnosed when the nerve conduction studies are affected. Strength Duration Time (SDTc) reflects nerve excitability properties and was previously used several times to demonstrate the excitability properties of the nerves in the existence of electrophysiologically developed diabetic polyneuropathy. But as we all know, diabetic patients may experience neuropathic symptoms even though their routine nerve conduction studies are normal. SDTc may be useful in this early stages of developing neuropathy. In this study we aimed to evaluate the SDTc properties of diabetic patients in this early preclinic stage. Recently SDTc was commonly studied in the upper extremities but most of the diabetic neuropathies are predominant in the lower extremities. So here we also studied both upper and lower extremities to demonstrate a possible difference.

Superficial radial neuropathy and brachioradial motor nerve palsy associated with proximal radius osteochondroma

The cutaneous branch of the radial nerve (superficial radial nerve, SRN) might be compressed or injured at various anatomical sites along its course in the forearm. Compression of the SRN occurring at the proximal third of the forearm is unusual. A 22-year-old man was admitted with pain and paraesthesia over the lateral aspect of his right wrist and thumb and pain at the elbow for six months. In electrodiagnostic testing, a sensory nerve action potential from the right SRN could not be recorded, while it was normal on the left. In a needle electromyography study, denervation potentials have been seen in the right brachioradial muscle and a decrease in interference pattern signals was also found. An exophytic lesion of the proximal radius was observed in radiographs. Computed tomography evaluation revealed an osteochondroma of the proximal radius. Neuropathies of the SRN and the brachioradial motor branch of the radial nerve are thought to be associated with proximal radial osteochondroma.

Clinical Properties of Regional Thalamic Hemorrhages

BACKGROUND Thalamic hemorrhage constitutes 6% to 25% of intracerebral hemorrhages. Vascular lesions affecting the thalamus may cause a variety of clinical symptoms. This retrospective study aims to evaluate localization of hemorrhage and clinical symptoms in patients with thalamic hemorrhage. METHODS One hundred and one patients with thalamic hemorrhage were examined retrospectively in our department. Hemorrhages were classified into 5 groups according to computed tomography: medial (thalamoperforate), anterolateral (tuberothalamic), posterolateral (thalamogeniculate), dorsal (posterior choroidal), and global. The relation between volume, localization, and penetration to adjacent structures/ventricles of hemorrhage and risk factors, clinical features, and prognosis were evaluated. RESULTS The study group included 101 patients. Eighty-two percent of the patients had hypertension, 19.8% had diabetes mellitus, 14.9% had cardiac disease, and 5.9% had chronic renal failure. Mean blood pressure was 173/101 mm Hg. Decreased Glasgow coma scale was significantly higher in the global hemorrhage group than in all regional groups (Chi-square, 10.54; P = .002). Medial group hemorrhages had a significantly higher rate than anterolateral, posterolateral, and dorsal intraventricular expansion. Out of speech disorders, 49% of patients had a right thalamic lesion (especially dysarthria) and 51% of patients had a left thalamic lesion (mostly aphasia). CONCLUSIONS In the study, we detected that the most important risk factor in thalamic hemorrhage is hypertension. The prognosis is worse in global and medial group hemorrhages, especially those which rupture to the ventricle, than the other groups. Thalamic lesions cause a variety of symptoms, including forms of aphasia, such as crossed dextral aphasia.

Increased asymmetric dimethylarginine level after antiepileptic drug treatment may be independent of the changes in plasma homocysteine level.

Increased asymmetric dimethylarginine level after antiepi-leptic drug treatment may be independent of the changes in plasma homocysteine level Dear Editor, We have read the recent article by Sniezawska and colleagues with great interest. 1 The authors investigated the frequency of polymorphism in the MTHFR (C677T), MTR (A2756G), and MTHFD1 (G1958A) genes and analysed the levels of homocysteine (Hcy), methionine, asymmetric dimethylarginine (ADMA), and arginine in epileptic patients treated with various antiepileptic drugs (AEDs). They found that AED pharmacotherapy in epileptic patients increases Hcy and ADMA levels. These authors suggested that their study showed an increase in Hcy level accompanied by an increase in ADMA level in epileptic patients receiving AEDs and concluded that hyperhomocysteinemia (HHcy) disrupts the feedback control of Hcy over ADMA. In the discussion, the authors cite Jonasson et al. 2 and Wanby et al. 3 who showed that patients with vascular disease undergoing long-term AED therapy experience HHcy, but the concentration of ADMA does not always increase. Unfortunately these authors did not study Hcy and ADMA levels during the long-term AED therapy. Elevated ADMA levels were first demonstrated in AED-treated epileptic patients in 2009. 4 In this study, the authors investigated the effect of valproic acid (VPA) and carbamazepine (CBZ) monotherapies on plasma levels of ADMA and Hcy and serum levels of folate and vitamin B12 in newly diagnosed epileptic patients. They found that ADMA levels significantly increased after the treatment in both VPA and CBZ groups. Homocysteine levels also increased in both the treatment groups, but the difference was significant only in the VPA group. The correlation between the changes in the ADMA and homocysteine levels was insignificant. Similarly, the difference between the mean ADMA change and mean homocysteine change was insignificant. Thus, these results showed that ADMA plasma levels were not associated with the harmonic changes in homocysteine. Surprisingly, Sniezawska et al. 1 did not cite this article in their study. In our opinion, the lack of discussion of the results of this study may leave readers with an incomplete understanding of the issue. We must consider whether increased ADMA after AED treatment is independent of the changes in plasma Hcy. and MTHFD1 gene polymorphisms compared to homocysteine and asymmetric dimethylarginine concentrations and their meta-bolites in epileptic patients treated with antiepileptic drugs. Hyperhomocysteinaemia is not associated with increased levels of asymmetric dimethylarginine in patients with ischaemic heart disease.

Electrophysiological Assessment of the Autonomic Nervous System in Male Patients with Acromegaly

Background/Aims: We aimed to electrophysiologically evaluate the autonomic function in acromegalic patients using sympathetic skin response (SSR) as a reflection of the sympathetic sudomotor activity and RR interval variation (RRIV) as an indicator of the cardiovagal autonomic function. Methods: The study group consisted of 18 male acromegalics, and the control group was composed of 18 age- and sex-matched healthy subjects. Participants underwent SSR and RRIV tests. Beginning latencies and amplitudes of the median and tibial SSRs were compared among the groups. The RRIV values recorded at rest and during hyperventilation were compared among the patients and controls. Results: Latencies of SSRs recorded from the palms (median) and soles (tibial) of acromegalics were significantly longer than in healthy subjects (p = 0.004, p < 0.001). The amplitude of SSR recorded from the sole (tibial) was significantly decreased (p = 0.028). The RRIVs obtained from acromegalics at rest and during hyperventilation were significantly decreased compared with those of controls (p < 0.001). The RRIVs obtained from controls prolonged significantly during hyperventilation (p < 0.001); however, in the acromegaly group, hyperventilation did not cause a significant change in RRIV (p = 0.983). Conclusions: The present study suggests that an autonomic dysfunction exists in patients with acromegaly. Dysautonomia in acromegalics may be documented by means of SSR and RRIV.