Interaural Comparison of Audiotory Brainstem Response in Unilateral Tinnitus Patients / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Tinnitus is a common symptom in otolaryngology. While there have been some animal studies of unique findings in auditory brainstem response (ABR), there have not been much reports related to ABR waves and tinnitus. Recently, some human studies have been reported on the specific characteristics of ABR wave in tinnitus patients. In this study, we compared waveform characteristics of the tinnitus ear with those of non-tinnitus ear in unilateral tinnitus patients. SUBJECTS AND METHOD: A retrospective review was carried out for 101 patients, who had been enrolled from January 2011 to April 2016 for the treatment of unilateral tinnitus. ABR parameters between the tinnitus ear and the normal ear were compared. The entire population was divided into two groups, a right tinnitus group and a left tinnitus group, and each group was compared interaurally. RESULTS: Latency delay and amplitude differences were observed in the ipsilesional wave III, but the ratio differences were not significant. The right tinnitus patient group showed an increased amplitude but no latency delay in the wave III and V. The left tinnitus patient group showed a latency delay in the wave I, III, and V and a decreased amplitude difference in the wave III. CONCLUSION: When the ABR waveform of unilateral tinnitus patients were compared interaurally, different ABR characteristics were observed between the right and left tinnitus. This may raise the possibility of a different pathophysiologic mechanism between the right and left ear.

Evaluation of Arterial Pulse Amplitude Ratio and Valsalva Ratio in Different Age Groups.

Aims: To construct normal values of Valsalva ratio for heart rate responses during Valsalva maneuver (VM) and arterial pulse amplitude ratio as reference values for different age groups, and to investigate the effect of aging alone , without , the presence of risk factors, on autonomic nervous system. This is a case control study, performed in Marjan teaching hospital, in Hilla city, from February 2012 to June 2012. Methodology: 40 subjects were included in this study, all were healthy males, group 1 (G1) mean age 28.3±9.7 years, group 2 (G2) mean age 48.4±7.1 years. Strips of lead II of ECG were recorded during performance of VM for calculation R-R intervals and measurement of blood pressure during phase I and phase II by mercury sphygmomanometer. Calculation of Valsalva ratio for heart rate and arterial pulse amplitude ratio for both groups were done. Results: The systolic and diastolic blood pressures of G2 were significantly higher than values of systolic and diastolic blood pressures of G1 at phase I and phase II of VM (P=0.05). Pulse pressure for the two groups at phase I (G1:51±11, G2: 53±13mmHg) and phase II (G1:41±5, G2:41±3.99) of VM were not significant (P>0.05). Valsalva ratio for G1 was (1.5±0.3) and for G2 was (1.39±0.29), pulse amplitude ratio for G1 was (0.80±0.19) and for G2 was (0.77±0.19). There were no significant differences between the two groups (P>0.05). All values were expressed as mean±SD. Conclusions: The results showed that the autonomic nervous system is intact in the older group. The aging process, without the presence of risk factors, does not affect the autonomic nervous system.

Detection of subclinical diabetic neuropathy: Potential factors affecting electrodiagnostic parameters

OBJECTIVES: To identify the factors that can potentially affect the ability of electrodiagnostic tests such as sural/radial amplitude ratio or SRAR and the presence of carpal tunnel syndrome or CTS to detect early subclinical neuropathy in diabetes mellitus (DM). Likewise, to investigate the likelihood of developing subclinical neuropathy that can be detected by a positive CTS or SRAR abnormalities, because of the presence of anthropometric factors and sugar levels, in addition to DM duration METHODOLOGY: A retrospective cohort study was undertaken among 144 DM type 2 patients with confirmed subclinical neuropathy. Demographic data such as age, height and age, body mass index (BMI) and blood glucose profiles were obtained. Nerve conduction findings (SRAR and CTS protocols) were statistically analyzed using two sample t-test and multiple logistic regression ratios RESULTS: Patients who were positive in the CTS protocols were taller and had lower BMI. They had shorter duration of DM but with extreme elevations in blood glucose. Variables that are independently associated with a (+) CTS are duration of DM, FBS, BMI, height and weight. Patients with SRAR abnormalities were older and obese, with longer duration of DM and less marked elevations in blood glucose. Variables that are independently associated with SRAR abnormalities are age, duration of DM, weight and BMI CONCLUSION: Factors such as age, duration of DM, weight and height, BMI as well as glucose control can potentially affect the ability of various electrodiagnostic tests (SRAR and the presence of CTS) to detect early subclinical neuropathy. Since confounding factors was different between CTS and SRAR, the pathogenesis of these conditions may be different. The likelihood of developing subclinical neuropathy that can be detected by a (+) CTS or SRAR abnormalities because of the presence of certain factors, were documented.

Comparison of Sural Nerve Amplitude and Sural/Radial Amplitude Ratio in the Electrodiagnosis of Diabetic Neuropathy

OBJECTIVE: To evaluate the usefulness of the sural/superficial radial sensory nerve action potential amplitude ratio (SRAR) in the electrodiagnosis of diabetic polyneuropathy. METHOD: Nerve conduction study was performed in 80 diabetic patients and 31 normal adults. Standard nerve conduction studies were performed. Sural nerve response was recorded with the active electrode on the posterosuperior margin of the lateral malleolus and stimulation 14 cm proximally. Superficial radial nerve response was recorded with the active on the snuffbox and stimulation 10 cm proximally. Baseline-to-peak sensory nerve action potential(SNAP) amplitudes were measured, and SRAR were obtained. The diabetic group was subdivided into an electro physiologically normal group (DMNL, n=32) and neuro pathy group (DMPN, n=48). SRAR was compared among the control (NORM, n=31), DMNL and DMPN groups. RESULTS: SRAR was 0.344 in NORM, 0.314 in DMNL and 0.145 in DMPN, respectively. SRAR showed 77.1% sensitivity and 93.8% specificity. Sural SNAP amplitude sensitivity was 85.4% and specificity, 88.7%. CONCLUSION: The relatively high specificity of SRAR indicates its usefulness in the diagnosis of diabetic polyneu ropathy. However, as the superficial radial sensory SNAP amplitude decreased significantly in the diabetic groups compared to control, the SRAR is not superior to the sural SNAP amplitude in the diagnosis of diabetic polyneuropathy.

Significance of Amplitude and Area Ratio of Compound Muscle Action Potential in Diagnosis of Diabetic Neuropathy

OBJECTIVE: The purpose of this study is to find out whether amplitude ratio and area ratio have correlation with nerve conduction velocity in the diabetes mellitus patients. METHOD: Median and deep peroneal motor nerve conduction study was performed in thirty-five normal control group and sixty diabetes mellitus patients group. The motor conduction velocity, amplitude ratio, and area ratio of the compound muscle action potential (CMAP) were measured. The experimental subjects were divided into 6 subgroups (in median nerve: M1, M2, M3, in peroneal nerve: P1, P2, P3) according to the median value of conduction velocity of each nerve; group M1 (n=35) and P1 (n=30): normal control group, group M2 (n=25) and P2 (n=30): below the median value of motor nerve conduction velocity in diabetes mellitus patients, group M3 (n=23) and P3 (n=29): above the median value of motor nerve conduction velocity in diabetes mellitus patients. RESULTS: There was no significant difference of area ratio between the each subgroups in both median and peroneal nerves. There was a significant difference of amplitude ratio between the M1 and M2 subgroups. There was a significant difference of amplitude ratio between the P1 and P2, P3 subgroups. CONCLUSION: According to above results, the decrease of amplitude of compound muscle action potential along with the decrease of conduction velocity seems to be helpful in the electrophysiologic diagnosis of diabetic neuropathy.

The usefulness of minimal F-wave latency and sural/radial amplitude ratio in diabetic polyneuropathy

The possibility of whether minimal F-wave latency and a simple ratio between the sural and superficial radial sensory response amplitudes may provide a useful electrodiagnostic test in diabetic patients was investigated in this report. To evaluate the diagnostic sensitivity of minimal F-wave latency, the Z-scores of the minimal F-wave latency, motor nerve conduction velocity (MCV), amplitude of compound muscle action potentials (CMAP), and distal latency (DL) of the median, ulnar, tibial, and peroneal nerve were compared in 37 diabetic patients. For the median, ulnar, and tibial nerves, the Z scores of the minimal F-wave latency were significantly larger than those of the MCV. In addition for all four motor nerves, the Z scores of the minimal F-wave latency were significantly larger than those for the CMAP amplitude. Furthermore, 19 subjects showing abnormal results in the standard sensory nerve conduction study had a significantly lower sural/radial amplitude ratio (SRAR), and 84% of them had an SRAR of less than 0.5. In conclusion, minimal F-wave latency and the ratio between the amplitudes of the sural and superficial radial sensory nerve action potential are sensitive measures for the detection of nerve pathology and should be considered in electrophysiologic studies of diabetic polyneuropathy.

Conduction Block in Carpal Tunnel Syndrome

OBJECTIVE: To demonstrate a conduction block of the median nerve at the flexor retinaculum (FR) in carpal tunnel syndrome (CTS), comparison of potentials obtained with stimulation of median nerve at the wrist and the palm may be required. METHOD: To determine the severity and incidence of conduction block in patients with CTS, seventy hands of neurologically healthy adults (mean age, 48 years) as control, and seventy hands of patients with CTS (mean age, 51 years) were tested. We performed median motor and middle finger recorded antidromic sensory conduction study with stimulation of the wrist and palm of a distance of 5 cm. The negative peak spike duration and baseline to peak amplitude of the compound muscle action potential (CMAP), and sensory nerve action potential (SNAP) with wrist and palm stimulations were measured. From these values, the wrist to palm duration ratio and amplitude ratio were obtained. RESULTS: The criteria of median motor nerve conduction block were a wrist to palm amplitude ratio of less than 0.7 and a wrist to palm duration ratio of less than 1.13. The criteria of median sensory conduction block were a wrist to palm amplitude ratio of less than 0.61 and a wrist to palm duration ratio of less than 1.33. In the patient group, 10 hands (14.3%) showed motor conduction block and 12 hands (17.1%) showed sensory conduction block and 3 hands (4.3%) showed both. The wrist to palm amplitude ratios of CMAP and SNAP in the patient showing conduction block were 0.6+/-0.1, and 0.4+/-0.2, respectively. There was no correlation between palm CMAP or SNAP amplitude and respective wrist to palm ratios. CONCLUSION: Comparison of the amplitude and duration of CMAP or SNAP obtained with stimulation of both wrist and palm may be able to differentiate between conduction block and axonal degeneration. These values may be useful in planning treatment and predicting outcome.

Differential Findings of Ictal EEG Pattern between Mesial and Neocortical Temporal lobe Epilepsies

BACKGROUND: Neocortical temporal lobe epilepsy (NTLE) appears to have different characteristics in clinical and electrophysiological aspects from mesial temporal lobe epilepsy (MTLE). Many semiological studies on TLE have been performed. We investigated ictal EEG patterns to differentiate NTLE from MTLE. METHODS: One hundred twenty nine scalp ictal EEG recordings came from 27 pathologically proven TLE patients were analyzed by 1) frequency of ictal discharge at EEG seizure onset (alpha, beta, theta & delta), 2) distribution patterns of ictal EEG onset (diffuse, lateralized & regionalized), 3) electrode of maximum amplitude at initial regionalized portion of ictal EEG, and 4) mesial to lateral and anterior to posterior amplitude ratio of ictal discharges in temporal electrodes. RESULTS: One hundred seven seizures came from MTLE (23 patients) and twenty-two seizures from NTLE (4 patients). Ictal EEG onset with delta wave was observed more frequently in MTLE (42.7%) than in NTLE (14.3%), but beta wave onset was noted more frequently in NTLE (14.3%) than MTLE (0%). Initial ictal EEG discharges were lateralized on ipsilateral hemisphere in 22.0% of MTLE and in 28.6% of NTLE, regionalized over ipsilateral temporal region in 36.6% and 23.8% respectively, and showed diffuse nonlateralized onset in 41.5% of MTLE and 47.6% of NTLE. Both TLE groups revealed most often their maximum negativity of ictal EEG onset at sphenoidal electrode (MTLE: 59.3%, NTLE: 42.8%). Mesial to lateral amplitude ratio of ictal EEG was significantly larger in MTLE group than NTLE group. The amplitude ratio of anterior to posterior temporal electrodes was greater in NTLE group than in MTLE group. CONCLUSION: Delta frequency of ictal onset EEG is more suggestive of MTLE while beta frequency may suggest NTLE. Initial ictal EEG patterns with their maximum on sphenoidal electrode do not differentiate MTLE from NTLE. NTLE has wide vertical and narrow horizontal electrical field, but MTLE has wide horizontal and narrow vertical electrical field.