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Biomedical subjects

M Ertaş

Publications and source records attributed to M Ertaş.

At least 19 recordsLinked to original sources
PubMed2003

Optimum trace count necessary for jitter calculation in single-fiber electromyography.

OBJECTIVE: To clarify the optimum trace count for jitter calculation. MATERIALS AND METHODS: Single-fiber electromyography was performed during voluntary contraction (VC-SFEMG) of extensor digitorum muscle in six healthy and five myasthenic subjects. Twenty single-fiber action potential (SFAP) pairs were recorded from each subject. For each pair, 100 consecutive traces were recorded and stored for off-line analysis. Ten different jitters were calculated in 10 consecutive steps for each SFAP pair by increasing the number of traces included to analysis (from 10 to 100). The jitter calculated in each step was compared with that calculated from 100 traces. RESULTS: Sixty was the optimum number of trace count for both myasthenics and normal controls. Using less than 60 traces for jitter calculation revealed lower values. CONCLUSION: Jitter calculation should be performed from at least 60 traces in VC-SFEMG. Less numbers yield lower jitter and may cause diagnostic error.

Action Potentials↗
PubMed2000

Concentric needle electrode for neuromuscular jitter analysis.

We used a concentric needle electrode (CNE) with 2 kHZ low-cut filter and a single fiber electrode (SFE) in the same subjects for neuromuscular jitter measurement in the extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles. At the same session, 20 jitter values were obtained from each subject with each electrode. For EDC (during voluntary contraction), mean jitter values with SFE and CNE were 23.4 +/- 8 micros and 23.3 +/- 8 micros in 10 normals; and 56.8 +/- 28 micros and 57.4 +/- 33 micros in 10 myasthenics. For OOc (during electrical stimulation), mean jitter values with SFE and CNE were 17.9 +/- 5 micros and 16.3 +/- 4 micros in 11 normal subjects, and 41.2 +/- 29 micros and 36.7 +/- 27 micros in 10 myasthenics. For both muscles, the numbers of individual abnormal jitter values with SFE and CNE were highly comparable. Both needles labeled the same patients as having "normal" or "abnormal" neuromuscular transmission. CNE may be an alternative to SFE in neuromuscular jitter analysis.

Adolescent↗
PubMed1998

Surface stimulation single-fiber electromyography.

Stimulation single-fiber electromyography (S-SFEMG) is an alternative method to SFEMG during voluntary contraction (VC-SFEMG). S-SFEMG is preferred to VC-SFEMG in uncooperating patients, children, and patients having severe weakness. Surface stimulation is a viable alternative to needle stimulation in S-SFEMG. In the present study, surface versus needle stimulation of facial nerve has been tested by recording from the orbicularis oculi and frontalis muscles. Jitter values obtained by both methods have been found to be nearly equal.

Adult↗
PubMed1997

A special kind of anterior horn cell involvement in juvenile myoclonic epilepsy demonstrated by macro electromyography.

Juvenile myoclonic epilepsy (JME) is not an uncommon seizure disorder, occurring in 5-10% of epileptic patients. A subclinical anterior horn cell involvement has been suggested in some JME patients by concentric needle electromyography (EMG) and turn/amplitude analysis. In this study, 22 JME patients and 17 normal control subjects have been studied with macro EMG, which is a sensitive method to assess the size of motor units. Most JME patients (19 of 22) had a pathologically increased number of individual large macro motor unit action potentials (MUAPs) compared to control subjects. For both biceps brachii and tibialis anterior muscles, means of median macro MUAP amplitudes were significantly greater than those of normal controls, whereas the fiber density values were only slightly increased. This suggested another kind of anterior horn cell involvement in JME than seen in motor neuron diseases.

Action Potentials↗
PubMed1997

Effects of bolus volume on oropharyngeal swallowing: an electrophysiologic study in man.

OBJECTIVE: Different variables of oropharyngeal swallowing change in response to bolus volume and consistency as determined by manometric/videofluoroscopic studies. But the subject is debatable especially from the physiologic point of view. No electrophysiologic studies are available on human subjects. METHODS: The effects of bolus volume and viscosity on different variables of oropharyngeal swallowing were investigated using electrophysiologic methods. Mechanical upward and downward laryngeal movements and submental electromyographic (SM-EMG) activity of the laryngeal elevator muscles were recorded during dry and 3-, 10-, and 20-ml water swallowing in 14 normal subjects. Cricopharyngeus (CP) muscle was investigated during 3- and 10-ml water swallowing in 10 normal subjects. Semisolid and liquid swallowing were compared in eight normal subjects. RESULTS: The total duration of SM-EMG, time necessary for larynx elevation, CP-EMG pause related with upper esophageal sphincter opening and swallowing variability (jitter) all increased significantly with increasing bolus volume. Laryngeal superior relocation time and CP-EMG pause were shorter for semisolid swallowing compared with swallowing the same amount of liquid. CONCLUSION: The duration of SM-EMG activity, laryngeal upward-downward movements, and CP-EMG pause are affected by sensory inputs such as volume and viscosity of the bolus swallowed. The results indicate that sensory input modifies the central swallowing pattern although basic events remain the same in normal human subjects.

Adolescent↗
PubMed1996

Slow motor conduction mainly limited to motor root in amyotrophic lateral sclerosis.

Motor conduction velocity is expected to be normal or nearly normal in amyotrophic lateral sclerosis (ALS). Some studies have suggested that pathology may be present in the proximal axons. Indeed, some investigators have shown a decrease in the proximal conduction velocity in ALS by using motor conduction velocity measurements and H-reflex and F-response recordings, but they could not delineate the precise region of the conduction pathology. In this study, unlike the ones carried out previously, the most proximal segment has been studied in 11 patients with ALS, 13 normal controls, and 5 patients with sequel of poliomyelitis (SPM) by recording sensory and motor spinal root potentials. While no conduction pathology, H-reflex, or F-response abnormalities were found in ALS patients compared to normal subjects, it was shown that conduction velocity decreased in the proximal segment of the lower motor neuron of the ventral root. Despite motor neuron pathology in SPM, there was no proximal motor conduction slowing compared with that in normal subjects.

Adult↗
PubMed1996

An electronic device measuring the frequency of spontaneous swallowing: digital phagometer.

A new and portable electronic device called the "Digital Phagometer" is described for the time based counting of spontaneous swallowing. This device is composed of a piezoelectric sensor and a digital event counter/ recorder which can be downloaded to any IBM-compatible PC. The sensor of Digital Phagometer is placed and fixed on the coniotomy region between the cricoid and thyroid cartilage. In this way, it is capable of sensing each upward and downward movement of the larynx produced by spontaneous movement as a function of time. Spontaneous swallowing was measured 1-4 h after lunch in 21 normal subjects and 21 patients with Parkinson's disease (PD). The mean frequency of spontaneous swallowing was 0.8 counts/min in PD patients and 1.18 counts/ min in normal subjects (p < 0.05). During the intake of 200 ml water, the mean frequency of voluntary swallowing did not differ significantly between the two groups (24.6 counts/min in normals vs. 22.3 counts/min in PD patients), but the time necessary to swallow the same volume of water was longer in the PD group.

Adult↗
PubMed1995

An electrophysiological investigation of deglutition in man.

This article describes a combined electrophysiological and mechanical method used to measure laryngeal movements and related submental EMG activity during swallowing. The mechanical upward and downward movements of the larynx were detected using a piezoelectric sensor while the submental integrated EMG (SM-EMG) was recorded. Measurements were performed in 29 human subjects. The interval between the onsets of the two sensor signal deflections was used as a measure of the time the larynx remained in its superior position during swallowing. In 10 subjects, the cricopharyngeus muscle (CP) of the upper esophageal spinchter showed a continuous tonic EMG activity except during swallowing. All the parameters measured were influenced by the type and volume of the bolus material. The method presented in this study proved its usefulness in the study of the physiology of deglutition as well as in its objective clinical evaluation in patients with dysphagia.

Adult↗
PubMed1995

A stable late soleus EMG response elicited by cortical stimulation during voluntary ankle dorsiflexion.

Transcranial electrical or magnetic stimulation was performed in 47 experiments on 42 normal adult subjects. Surface compound muscle action potentials were recorded from the antagonistic tibialis anterior (TA) and soleus (SOL) muscles. A stable late response recorded from SOL during voluntary ankle dorsiflexion is described and called soleus MEP-80. Its origin has been studied with different experimental procedures. (1) It is only obtained during active voluntary dorsiflexion of the ankle within 70-100 msec (mean 86.9 +/- 6.4 msec) whereas passive dorsiflexion does not promote such a response. The size of SOL MEP-80 was always bigger than the primary SOL response. (2) A similar constant response has not been obtained during voluntary plantar flexion from SOL and TA muscles. (3) SOL MEP-80 is not changed significantly by the Jendrassik manoeuvre. (4) It is not obtained or is suppressed when the subject is sitting with the feet free in space. On the other hand, it is obtained when the subject is standing, especially when standing is made difficult. (5) SOL MEP-80 has not been obtained by brain-stem, spinal cord or root stimulation. (6) A later response of longer than 100 msec latency was sometimes obtained at rest but such an S100 soleus response was abolished or transformed to the SOL MEP-80 immediately during ankle dorsiflexion. (7) It is concluded that SOL MEP-80 is a polysynaptic extensor response related to postural mechanisms and originating through convergence of descending motor commands and peripheral sensory feedback.

Adult↗
PubMed1994

Comparison of magnetic coil stimulation and needle electrical stimulation in the diagnosis of lumbosacral radiculopathy.

Electrical stimulation (ES) of lumbosacral nerve roots using a needle electrode inserted to the laminar level at the midline of Th12-L1 or L1-2 intervertebral interspace, was compared with magnetic stimulation using a 9-cm diameter coil (MCS) at the L3-4 or L4-5 spine levels, Compound muscle action potentials (CMAP) were superficially recorded from homologous muscles in both sides in 15 normal control subjects and in 20 patients with lumbosacral radiculopathy. Soleus muscles were used for S1, tibialis anterior (TA) for L5, and rectus femoris (RF) muscles for L4 roots. According to the clinical or radiological diagnosis (CAT, MRI and/or myelography) conventional needle EMG was capable to localise the root lesion in 16 of 20 patients (80%) and ES localised the root involvement in 18 of 20 patients (90%); the diagnostic value of MCS was lower, about 65% (13 of 20 patients). Although ES is uncomfortable and invasive, it is superior to needle EMG in localising unilateral or multiple lumbosacral root involvement. At present, MCS is not suitable for the diagnosis of lumbar radiculopathy.

Adult↗
PubMed1994

Ice test as a simple diagnostic aid for myasthenia gravis.

It is known that myasthenia gravis is improved by cold. In two previously reported studies performed on a limited number of myasthenic patients and controls, local cold application to the eyelid was suggested for use as a diagnostic test for ocular myasthenia gravis. In this study, ice test to the eyelid was evaluated as a diagnostic test on 12 myasthenic patients and 15 controls with blepharoptosis and the results were compared with those of edrophonium test.

Adolescent↗
PubMed1994

Diagnostic value of electrical stimulation of lumbosacral roots in radiculopathies.

Needle electrical stimulation of the lumbosacral roots at the laminar level of the Th12-L1 or L1-2 intervertebral spaces were performed in 24 normal subjects and 58 patients with various kinds of lumbar radiculopathy (unilateral L4, L5 and S1 herniated nucleus pulposus and lumber stenosis). The root stimulation method was compared with conventional needle EMG. Lumber electrical stimulation showed root abnormalities objectively in 80% of patients while the diagnostic value of needle EMG was 65%. Therefore, electrical root stimulation is superior to routine EMG for localizing lumbar root involvement. However, the only needle EMG demonstrated the root pathology in 7 cases (12%) and single electrophysiological abnormality was found by the root stimulation in 16 cases (27%). Thus, both electrophysiological methods should be complementary to each other in evaluation of the lumbar radioculopathy.

Action Potentials↗
PubMedDate not supplied

Pharmacokinetics of carbamazepine. Part I: A new bioequivalency parameter based on a relative bioavailability trial.

The relative bioavailability of three carbamazepine generics available in Turkey, were investigated in 5 healthy male volunteers. When issuing a license to any drug, FDA stipulates at most a difference of 20% from the reference drug only in peak concentration and AUC (area under the curve). This condition may cause some problems, as two generics of the same drug can yield the same total amount (AUC) and can be accepted as bioequivalent despite different curves of the two drugs. In this study, to compare drugs from the point of view of bioequivalency, we suggest a new calculation method that takes into account ka (absorption rate constant), ke (elimination rate constant), tmax (time to peak), MRT (mean residence time) and AUC. Should this formula be used in comparison of bioequivalency, all the parameters related to the kinetics of drugs will have been taken into account. The suggested parameter is: [formula: see text] However, amongst three carbamazepine generics-Tegretol, Temporol and Karazepin-the most desirable curve is that of Tegretol, while bioavailability values are respectively F = 0.86, 0.93, 0.85 and AUC = 145, 161, 127. The A parameter values are respectively 49.3, 47.2, 42.9.

Adult↗
PubMedDate not supplied

Subclinical anterior horn cell involvement in juvenile myoclonic epilepsy.

Although clinical signs of muscle wasting and weakness were not present, electromyographic (EMG) evidence of subclinical anterior horn cell involvement of spinal cord was noted in 5 patients with juvenile myoclonic epilepsy (JME). Quantitative interference pattern analysis of EMG recorded from the anterior tibial muscle showed that the ratio (amplitude:turn/turn:second, A:T/T:S) was significantly increased in 10 patients with JME and 12 patients with lower motor neuron disorders (LMND) as compared with those of 22 normal subjects and 15 patients with frequent generalized tonic-clonic seizures (GTC). Subclinical anterior horn cell involvement detected by EMG techniques can be related to a genetically determined component of JME.

Adolescent↗
PubMedDate not supplied

F wave parameters and F tacheodispersion in mild diabetic neuropathy.

F tacheodispersion and some F wave parameters have previously been suggested to be useful in the detection of peripheral nerve involvement in diabetic patients with normal nerve conduction studies. In this study, ulnar and tibial F wave parameters of diabetic cases with normal motor and sensory nerve conduction studies (Group 1) were calculated, F tacheodispersion histograms were constructed and compared with the same parameters obtained from the normal controls (Control group) and diabetic cases with abnormal motor and sensory nerve conduction examinations (Group 2). There was a tendency towards lower conduction velocities in ulnar and tibial tacheodispersion histograms of Group 1 and Group 2, as compared to Control group. Most of the F wave values were significantly abnormal in Group 2 in comparison to other two groups, whereas statistically significant differences between Group 1 cases and Control group were found in minimum ulnar F wave conduction velocity (FCVmin), mean ulnar FCV (FCVmean), tibial FCVmin and tibial FCVmean values. Unlike other methods, F waves give information about the entire length of the motor nerve fiber. In mild neuropathies, in which nerve fibers are damaged uniformly, testing the whole length of a nerve with this method may be beneficial in detection of a mild conduction abnormality.

Adult↗
PubMedDate not supplied

Disposable concentric needle electromyography electrodes artifact discharge mimicking positive sharp waves.

OBJECTIVES: To determine a new artifact discharge produced from the disposable concentric needle (DCN) electromyography (EMG) electrodes. METHODS: We have recorded the activity obtained after the first insertion of 41 DCN (37 mm) and 36 DCN (50 mm) in several muscles during the rest. The number of the patients was 77 (26 males, 51 female). RESULTS: We observed an artifact discharge (AD) resembling positive sharp waves (PSWs) in 31 patients of 77 insertions. The AD occurred with 18 of 41 insertions of DCN 37 mm and 13 of DCN 50 mm. The artifact resolved when the needle has been moved in the muscle or in the adipose subcutaneous tissue. CONCLUSION: This AD should be recognized when using DCN electrodes to avoid confusion with PSWs. Recognizing these artifacts during needle EMG is important to avoid false positive results.

Adolescent↗