Fikret Bademkiran

Central and peripheral motor conduction to cremasteric muscle

The few electrophysiologic studies of the cremasteric muscle (CM) have mainly been restricted to the cremaster reflex with no reference to central and peripheral nerve conduction to the muscle, probably for technical reasons.Twenty‐six normal adult male volunteers were studied by transcranial magnetic cortical stimulation (TMS) and stimulation of thoracolumbar roots. The genitofemoral nerve (GFN) was stimulated electrically at the anterior superior iliac spine and a needle electrode was inserted into the CM for conduction studies. The motor latency to the CM from the cortical TMS ranged from 20 to 33 ms among the subjects (25.8 ± 2.9 ms, mean ± SD). Magnetic stimulation of the lumbar roots produced a motor response of the CM within 9.6 ± 1.9 ms (range, 6–15). The central motor conduction time to the CM was 16.5 ± 2.8 ms (range, 10–21). Stimulation of the GFN produced a compound muscle action potential with a mean value of 6.4 ± 1.8 (range, 4–10) ms in 23 of the 26 cases. Thus, central motor nerve fibers to the CM motor neurons exist, and there may be a representation area for the CM in the cerebral cortex. The GFN motor conduction time to the CM may have clinical utility, such as in the evaluation of the groin pain due to surgical procedures in the lower abdomen. Muscle Nerve, 2005

Electrophysiological evaluation of the genitofemoral nerve in patients with inguinal hernia

Groin pain in the lower abdomen but including the ilioinguinal region is frequent after inguinal hernia operations, but the integrity of the nerves in this region, including the genitofemoral nerve (GFN), has not been investigated. We studied GFN motor conduction time to the cremasteric muscle (CM), the CM electromyogram (EMG), and the CM reflex in 30 patients with unilateral inguinal hernia who underwent herniorrhaphy and in 26 similar patients who had no surgical intervention. Among the 30 patients undergoing herniorrhaphy, 14 (47%) showed motor involvement of the GFN, whereas 6 of the 26 (23%) patients not treated surgically had involvement of the GFN. These findings indicate that subclinical motor involvement of the GFN can be demonstrated by electrophysiological methods and is common after inguinal herniorrhaphy. Based on patient complaints, the herniated mass may also be responsible for motor involvement of the GFN in some patients before surgery. Muscle Nerve, 2005

Sensory conduction study of the infrapatellar branch of the saphenous nerve

Although neuropathies of the infrapatellar nerve (infrapatellar branch of the saphenous nerve, IPBSN) have been reported clinically, no electrophysiological method has been defined to evaluate IPBSN conduction. We therefore studied a total of 60 saphenous nerves and 60 IPBSNs from 36 volunteers. The IPBSN was stimulated medially with a surface electrode 2 cm below the patella. The response was recorded with a needle electrode located close to the nerve 1 cm lateral to the femoral artery in the inguinal region. Sensory nerve action potentials were obtained from each subject; mean latency of the first positive peak was 8.1 ± 0.9 ms, conduction velocity was 54 ± 4.4 m/s, and response amplitude was 1.3 ± 1.1 μV. The method that we describe may be an easy and useful electrophysiological test for neuropathies of the IPBSN. Muscle Nerve, 2006

Effects of a Dynamic Warm-Up, Static Stretching or Static Stretching with Tendon Vibration on Vertical Jump Performance and EMG Responses

Abstract The purpose of this study was to investigate the short-term effects of static stretching, with vibration given directly over Achilles tendon, on electro-myographic (EMG) responses and vertical jump (VJ) performances. Fifteen male, college athletes voluntarily participated in this study (n=15; age: 22±4 years old; body height: 181±10 cm; body mass: 74±11 kg). All stages were completed within 90 minutes for each participant. Tendon vibration bouts lasted 30 seconds at 50 Hz for each volunteer. EMG analysis for peripheral silent period, H-reflex, H-reflex threshold, T-reflex and H/M ratio were completed for each experimental phases. EMG data were obtained from the soleus muscle in response to electro stimulation on the popliteal post tibial nerve. As expected, the dynamic warm-up (DW) increased VJ performances (p=0.004). Increased VJ performances after the DW were not statistically substantiated by the EMG findings. In addition, EMG results did not indicate that either static stretching (SS) or tendon vibration combined with static stretching (TVSS) had any detrimental or facilitation effect on vertical jump performances. In conclusion, using TVSS does not seem to facilitate warm-up effects before explosive performance.

Morphology and Innervation of the Human Cremaster Muscle in Relation to its Function

The electromyographic properties of the cremaster muscle (CM) are quite different from other skeletal muscles. It shows excessive spontaneous discharges, and the motor unit shape and firing frequency of the CM muscle differ from that of limb muscles. In this study, CM of six adult cadavers and six orchiectomy specimens were used to reveal the detailed histology of the muscle and provide an anatomophysiological explanation for these unusual electromyographic properties. Routine histochemical stains revealed the CM was composed of several distinct bundles of smooth and striated muscle fibers within connective tissue. The smooth muscle fibers that were more profuse than previously known and were not arranged in layers, but widely dispersed between striated muscle fibers. Bielschowsky silver staining technique, anti‐neurofilament and anti‐synaptophysin immunostaining showed the presence of multiple motor end‐plates observed as a series of small dots or lines running along the striated muscle fibers and several nerve endings on a single muscle fiber. Myosin immunostaining confirmed the CM is a slow‐twitch muscle, and α‐actin smooth muscle immunostaining confirmed the presence of a large number of smooth muscle fibers. There were also small multipolar neurons forming nerve plexuses between smooth muscle fibers. Anti‐GFAP immunostaining confirmed the presence of glial cells similar to astrocytes. In conclusion, the findings of this detailed anatomical study showed the CM, widely known as a striated muscle, contains a large number of smooth muscle fibers, and the spontaneous electromyographic discharges are due to the presence of multiple motor end‐plates and dense innervation. Anat Rec,291:790‐796, 2008.

Cutaneous silent periods of the vastus medialis evoked by the stimulation of lateral femoral cutaneous nerve

OBJECTIVE Cutaneous silent period (CSP), which is a spinal reflex mediated by A-delta cutaneous afferents, is transient suppression of the electromyographic activity. In this study, our aim is to investigate CSPs of vastus medialis muscle (vm-CSP) evoked by the stimulation of the lateral femoral cutaneous nerve (LFCN) in healthy controls and in patients with meralgia paresthetica (MP). METHODS Twenty-one patients with MP (17 unilateral, 4 bilateral) and 27 healthy controls were included. Nerve conduction studies of LFCN and vm-CSP were analyzed in all subjects. A stimulus train consisting of five electrical shocks was applied to the skin at the anterolateral side of the thigh for recording of the vm-CSP. RESULTS Nerve conduction abnormalities of LFCN were observed in all patients with MP. Mean duration of vm-CSP was 69.7+/-9.2ms, and mean onset latency was 44.7+/-6.9 in healthy controls. Onset latency of vm-CSP was significantly prolonged and the duration of vm-CSP was significantly shortened in patients with MP. Vm-CSP abnormalities were observed in 20/25 extremities with MP. CONCLUSIONS Dysfunction of A-delta afferents may cause these findings in patients with MP. Additionally, spinal modulation of pain may also play a role in the explanation of our findings. SIGNIFICANCE The present study demonstrates the CSP alterations in the patients with entrapment neuropathy of a cutaneous nerve.

Myasthenia gravis and thymoma coexisting with myotonic dystrophy type 1

We describe a 34-year old man presenting with subacute generalized myasthenic symptoms. His clinical features and laboratory investigations demonstrated both myasthenia gravis and myotonic dystrophy type 1. The computerized tomography of chest revealed anterior mediastinal mass. The lymphocyte-rich thymoma was removed surgically and he received radiotherapy. Recent observations suggested that the patients with myotonic dystrophy may have an increased risk of benign and malignant tumours but its coexistence with thymoma is very rare. The risk of thymoma associated with myotonic dystrophy is unknown.

ADDUCTOR T AND H REFLEXES IN HUMANS

In the belief that changes in the adductor reflex (AR) may be helpful in evaluating lumbar root and plexus lesions, expression of the AR was studied in 43 healthy human subjects. ARs elicited with an electronic reflex hammer were recorded from the inner side of the proximal thigh using needle and surface electrodes, and patellar reflexes (PRs) were recorded simultaneously. These reflexes were obtained by tapping the ipsilateral medial aspect of the knee, the contralateral patellar tendon, the ipsilateral and contralateral anterior superior iliac spines, and the Achilles tendon. The H reflex of the obturator nerve was also evaluated in 17 cases. ARs were evoked consistently by tapping the ipsilateral medial aspect of the knee and by contralateral patellar tap, and by tapping ipsilateral and contralateral anterior superior iliac spines when a needle recording electrode was used. Sometimes an Achilles tendon tap also elicited the AR ipsilaterally. By contrast, the PR could only be elicited by a tap to the ipsilateral patellar tendon. ARs have somewhat different features than other well‐known tendon reflexes such as the PR and are recorded consistently when a needle electrode is used, being elicited from both distal and proximal areas of the legs by tapping the Achilles tendon or anterior superior iliac spines unilaterally or bilaterally. Their role in evaluating lumbar root disease and monitoring adductor spasticity merits investigation. Muscle Nerve, 2006

Telbivudine in liver transplant recipients: Renal protection does not overcome the risk of polyneuropathy and myopathy

The recently reported benefit of telbivudine for renal function has not been systematically studied in long‐term liver transplantation (LT) recipients who are at high risk for renal impairment. We aimed to examine whether switching lamivudine therapy to telbivudine could improve renal function in LT recipients who have impaired renal function. This single‐center, prospective cohort study enrolled LT recipients who were on lamivudine for hepatitis B virus (HBV) prophylaxis and who had renal impairment for at least 1 year. Lamivudine was switched to telbivudine. The primary outcome was to evaluate the change in renal function at weeks 12, 24, 36, and 48. The secondary outcomes were to assess the efficacy of telbivudine for HBV prophylaxis and the safety profile of telbivudine in the posttransplant setting. After 45 patients were enrolled, the study was terminated early because of increased rates of polyneuropathy/myopathy. During telbivudine treatment (median, 64 weeks), estimated glomerular filtration rate (eGFR) increased in 34 patients (76%). The improvement in renal function was prominent after 24 weeks of telbivudine treatment. Telbivudine was effective as prophylaxis against HBV recurrence. Twenty‐six patients (58%) developed polyneuropathy and/or myopathy. The 1‐year estimated incidence of polyneuropathy/myopathy was 28%. Diabetes was the strongest predictor of polyneuropathy/myopathy (hazard ratio, 4.13; 95% confidence interval, 1.49‐11.50; P = 0.007). In conclusion, although it seems to have a favorable effect in the improvement of renal function and seems to be effective in the prevention of HBV recurrence, the high risk of polyneuropathy and myopathy hampers the use of telbivudine in LT recipients. Liver Transpl 21:1066‐1075, 2015.

WITHDRAWAL REFLEXES IN ADDUCTOR MUSCLES ELICITED BY ELECTRICAL AND MAGNETIC STIMULATION OF THE OBTURATOR NERVE

The withdrawal reflex in the short head of the biceps femoris muscle after electrical stimulation of the sural nerve at the ankle has been investigated in numerous studies. These studies have described two distinct responses: early (R‐II) and late (R‐III). However, withdrawal reflex activity of the adductor muscles in the legs has not been studied systematically. Adductor muscle reflex activity is important because it can produce serious clinical problems, such as adductor spasticity and spasms, during bladder surgery. The present study examined withdrawal reflex features of adductor muscles obtained by electrical and magnetic stimulation of the obturator nerve (ON) in 34 normal healthy subjects. Early adductor muscle withdrawal reflex responses were elicited by ipsilateral ON electrical stimulation with a mean latency of 45.7 ± 2.0 ms (responses in 94% of subjects). Reflex responses were also obtained using magnetic stimulation at a similar incidence rate. Contralateral ON electrical stimulation resulted in a similar reflex, but with a lower incidence. ON and femoral nerve electrical and magnetic coil stimulation produced similar low‐incidence responses in the vastus medialis. These findings indicate that short latency adductor withdrawal reflexes are easily obtained on both sides following electrical or magnetic stimulation of the ON, and they can be elicited by both nociceptive and nonnociceptive stimuli. These reflexes prepare the body for a proper response to incoming signals and likely serve to protect the pelvic floor and pelvic organs. Muscle Nerve, 2008