Electrodiagnostic Study of the Patients with Suspected Carpal Tunnel Syndrome.

BACKGROUND: Various electrodiagnostic tests are employed for diagnosis of carpal tunnel syndrome reporting wide range of sensitivity and specificity for each test in clinical practice. Therefore, the aim of our study is to assess the sensitivity of electrodiagnostic tests used in our set up for the diagnosis of carpal tunnel syndrome. METHODS: This cross-sectional study consisted of 21 patients suspected with carpal tunnel syndrome who were referred to neurophysiology lab for electrodiagnostic evaluation and 21 age-group gender matched healthy controls. Digit 4, lumbrical versus ulnar interossei latencies and conventional nerve conduction variables were recorded. A p value of less than 0.05 was considered significant. RESULTS: The sensitivity of median versus ulnar digit 4 sensory latency difference was the highest (72.72 %) whereas the conduction velocity of median nerve was the lowest (45.45%). The lumbrical versus ulnar interossei latency difference was significant between groups; however the sensitivity was only 51.52%. The conduction velocity of median nerve was relatively slower in the suspected cases than controls (49.67±13.75 vs. 60.90 ±6.70; p=0.007). The distal sensory latency of median nerve was significant between groups (3.47 ±0.58 vs. 2.16±0.25; p=0.03). The distal and proximal latencies of motor median nerve were significant between suspected cases and controls (4.70±1.82 vs. 2.75±0.38; p=<0.001). CONCLUSIONS: The sensitivity of median versus ulnar digit 4 sensory latency difference was the highest in our set up therefore, addition of this test with conventional method can be helpful in achieving a higher diagnosis rate.

Mean Motor Nerve Conduction Velocity of Right Ulnar Nerve among Physically Trained Adult Males in a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: Neural adaptation to physical training allows a person to better coordinate the activation of all relevant muscles producing maximum force. Nerve conduction velocity measures the speed of impulse along the motor neuron and is strongly associated with muscle contraction time. This study aimed to find out the mean motor nerve conduction velocity of the right ulnar nerve among physically trained adult males in a tertiary care centre. Methods: This descriptive cross-sectional study was conducted in the Neurophysiology Laboratory of a tertiary care centre from 3rd November, 2019 to 2nd November, 2020. Thirty young adult males who were engaged in the physical training at a training centre for more than 3 months were studied after receiving ethical approval from the Institutional Review Committee (Reference number: 1578/019). Motor nerve conduction parameters of the right ulnar nerve were measured and data were entered in Microsoft Excel. Statistical analysis was done using the Statistical Packages for the Social Sciences version 25.0. Point estimate at 95% Confidence Interval was calculated along with frequency and percentages for binary data, and mean and standard deviation for continuous data. Results: Among 30 males studied, the mean motor nerve conduction velocity of the ulnar nerve was found to be 61.02±5.86 m/sec (58.92-63.11 at 95% Confidence Interval). The mean distal latency and amplitude of the muscle action potential were 2.33±0.53 ms and 8.08±1.17 mv respectively. Conclusions: Our study found that the mean nerve conduction velocity of the ulnar nerve was similar when compared to studies conducted in similar settings. Keywords: Nepal; nerve conduction; ulnar nerve.

Cardiovascular Reactivity to Acute Mental Stress in Post Ovulatory Females.

BACKGROUND: Female hormones fluctuate with the phases of menstrual cycle. Estrogen, which has attributes in cardio-protection, is secreted less during luteal phase. In post-ovulatory phase, days 1-2 before menstruation has minimal female hormone influence due to less secretion. Mental stress subjected at this phase might enhance sympathetic activation which in long run may precipitate cardiovascular diseases. Hence, to explore the autonomic activity to mental stress during this phase of menstrual cycle the study was undertaken. METHODS: Thirty apparently healthy young postovulatory female medical students of B. P. Koirala Institute of Health Sciences, Nepal of age 19.93 (± 0.91) years with BMI of 20.70 kg/m2 (± 2.49) kg/m2 were recruited for the present study. Their short term heart rate variability (HRV) of 5 min was recorded during rest at sitting position. Then each subject was given a mental stress (nine questions selected from MENSA workout questionnaire) for 5 min. During the stress, HRV was recorded simultaneously. Data was statistically analyzed using Friedman test followed by multiple comparisons. The p<0.005 was considered statistically significant. RESULTS: Mental stress significantly decreased RMSSD (p= 0.001), NN50 (p= 0.001) and PNN50 (p=0.001) in time domain and HF nu (p=0.012) in frequency domain parameters of HRV. CONCLUSIONS: Young healthy post ovulatory females responded to acute mental stress by withdrawing cardiac parasympathetic activity.

Severe Cardiac Dysautonomia and Sudden Death in a Patient Presenting with Anginal Symptoms in Absence of Cardiovascular and Other Diseases: A Case Report.

Angina is a type of chest pain, experienced by patients with ischemic heart diseases. Cardiac autonomic modulation as assessed by heart rate variability and baroreflex sensitivity is found reduced in ischemic heart disease patients. Marked reduction in heart rate variability and baroreflex sensitivity in ischemic heart disease patients is found associated with sudden cardiac death. We report a case of a 35-year-old man who presented with angina for the last few months. Thorough investigations showed no evidence of any cardiac or other systemic diseases. However, his cardiovascular autonomic modulation (as assessed by heart rate variability) and spontaneous baroreflex sensitivity were markedly reduced. The patient had sudden death within 6 months of follow-up. Reportedly, no other specific abnormalities were found before death. This case report suggests that patients presenting with typical chest pain as angina may have severe dysautonomia and risk of sudden death even in the absence of cardiovascular or any other known end-organ diseases.

Effect of long term high altitude exposure on cardiovascular autonomic adjustment during rest and post-exercise recovery.

BACKGROUND: Despite the successful adaptation to high altitude, some differences do occur due to long term exposure to the hypoxic environment. The effect of long term high altitude exposure on cardiac autonomic adjustment during basal and post-exercise recovery is less known. Thus we aimed to study the differences in basal cardiac autonomic adjustment and its response to exercise in highlanders and to compare it with lowlanders. METHODS: The study was conducted on 29 healthy highlander males who were born and brought up at altitude of 3000 m and above from the sea level, their cardiac autonomic adjustment was compared with age, sex, physical activity and ethnicity-matched 29 healthy lowlanders using Heart Rate Variability (HRV) during rest and recovery from sub-maximal exercise (3 m step test). Intergroup comparison between the highlanders and lowlanders and intragroup comparison between the rest and the postexercise recovery conditions were done. RESULTS: Resting heart rate and HRV during rest was comparable between the groups. However, heart rate recovery after 3 min step test was faster in highlanders (p < 0.05) along with significantly higher LF power and total power during the recovery phase. Intragroup comparison of highlanders showed higher SDNN (p < 0.05) and lower LF/HF ratio (p < 0.05) during recovery phase compared to rest which was not significantly different in two phases in lowlanders. Further highlander showed complete recovery of RMSSD, NN50, pNN50 and HF power back to resting level within five minutes, whereas, these parameters failed to return back to resting level in lowlanders within the same time frame. CONCLUSION: Highlanders completely recovered back to their resting state within five minutes from cessation of step test with parasympathetic reactivation; however, recovery in lowlanders was delayed.

Nerve Conduction and Heart Rate variability in Patients with Hypothyroidism at a Tertiary Care Centre in Eastern Nepal.

INTRODUCTION: Thyroid hormone effects on many organs including central and peripheral nervous systems. However, these hormones do not affect all systems/organs to a similar extent. Thus, we conducted this study to explore the effect of thyroid hormones on somatic nervous system assessed by Nerve conduction study and cardiac autonomic activity assessed by heart rate variability. METHODS: The study included newly diagnosed hypothyroid patients and healthy controls. In all subjects NCS were performed in median, ulnar, tibial and sural nerves using Nihonkohden machine Cardiac autonomic control was assessed using Short-term Heart Rate Variability and parameters were analyzed by Time Domain and Frequency Domain methods. RESULTS: Both the groups were comparable in term of age, Body Mass Index, Pulse Rate, Systolic Blood Pressure and Diastolic Blood Pressure. Sensory parameters of NCS showed significant decrease in left median nerve SNAP amplitude (38.24±10.23 Vs 31.59±14.06, P=0.048) and nerve conduction velocity of bilateral median nerve in hypothyroid patients. In motor parameters of NCS, onset latencies of bilateral median nerves and right ulnar nerve were significantly increased in hypothyroid patients. All Time Domain measures of HRV and Frequency Domain measures; LF Power, HF Power and Total Power were significantly decreased (P<0.05) in hypothyroid patients. These HRV parameters are indicators of parasympathetic activity. CONCLUSIONS: In newly diagnosed hypothyroid patients, especially median nerve functions (both sensory and motor) and parasympathetic activity were decreased. It reflects that in hypothyroidism both autonomic nervous system and other somatic nerves are not affected in a similar extent.

Nerve conduction studies in lower limb of elite Nepalese football players: an insight into neural adaptations.

BACKGROUND: The study was aimed to assess somatic neural alterations in lower limbs of elite Nepalese football players by comparing their nerve conduction parameters with non-athletic controls. METHODS: Players (N.=27, age 22.74±2.52 yrs.) with excellent cardio-respiratory fitness and presenting no signs of injuries, and sedentary controls (N.=29, age 23.41±2.95 yrs.) were recruited for the study. Standard nerve conduction techniques were applied to evaluate posterior tibial and sural nerves in the dominant and non-dominant limbs of each individual. Conduction velocity, onset latency, amplitude and duration of the motor and sensory evoked responses were recorded. RESULTS: The players had significantly lower resting mean heart rate, systolic and diastolic blood pressure than controls. Tibial compound muscle action potential (CMAP) showed higher amplitude as compared to controls; tibial proximal CMAP amplitude [(13.624±4.57) vs. (10.810±4.62) mV, P=0.035] of dominant leg, tibial proximal [(13.893±4.60) vs. (11.083±4.51) mV, P=0.045] and distal [(16.388±3.62) vs. (13.958±4.65) mV, P=0.049] amplitude of non-dominant leg. Likewise, players had significantly shorter tibial CMAPs duration of each lower limb compared with corresponding limb of controls. Sural nerve of non-dominant leg revealed shortened sensory nerve action potential duration [(1.729±0.25) vs. (1.904±0.289) ms, P=0.018]. CONCLUSIONS: Increased tibial CMAP amplitude and decreased CMAP duration in players suggest excitation of more number of motor units and higher synchronicity of muscle fibers' discharge than in controls respectively. Higher amplitude can also be attributed to increase in muscle fiber size and/or efficiency of neuromuscular transmission. Increased synchronicity indirectly reflects narrow range of conduction velocity among tibial neurons. The adaptive changes in somatic nerves need more crucial research for exact identification of sites and the structures responsible.

Somatic neural alterations in non-diabetic obesity: a cross-sectional study.

BACKGROUND: Reports on alterations in somatic neural functions due to non-diabetic obesity, a major risk factor for diabetes, are few and still a matter of debate. Nevertheless, to our knowledge, reports lack any comments on the type of somatic nerve fibers affected in non-diabetic obesity. Therefore, this study aimed to find out the alteration in somatic neural functions in non-diabetic obese persons if any. METHODS: The study was conducted on 30 adult non-diabetic obese persons (mean age 32.07 ± 7.25 years) with BMI > 30 Kg/m2 (mean BMI 30.02 ± 2.89 Kg/m2) and 29 age- and sex-matched normal weight controls (mean age 30.48 ± 8.01 years) with BMI: 18-24Kg/m2 (mean BMI 21.87 ± 2.40 Kg/m2). Nerve conduction study (NCS) variables of median, tibial and sural nerves were assessed in each subject using standard protocol. The data were compared by Mann Whitney 'U' test. RESULTS: In comparison to normal weight persons, obese had lower compound muscle action potential (CMAP) amplitudes of right median [9.09(7.62-10.20) Vs 10.75(8.71-12.2) mV, p = 0.025] and bilateral tibial nerves [Right: 8.5(7.04-11.18) Vs 12.1(10.55-15) mV, p < 0.001 and left 9.08(6.58-11.65) Vs 13.05(10.2-15.6) mV, p = 0.002]. Furthermore, obese persons had prolonged CMAP durations of right and left median [10.5(9.62-12) Vs 10(8.4-10.3) ms, p = 0.02 and 10.85(10-11.88) Vs 10(9-10.57) ms, p = 0.019] and right tibial [10(9-11) 8.5(7.92-10) ms, p = 0.032] nerves. Sensory NCS (sural nerve) also showed diminished sensory nerve action potential (SNAP) amplitude [16(12.08-18.21) vs 22.8(18.3-31.08) µV, p < 0.001] and prolonged duration. However, onset latencies and conduction velocities for all nerves were comparable between the groups. CONCLUSION: This study documents subclinical peripheral nerve damage in non-diabetic obese with abnormal NCS parameters; shorter amplitudes and prolonged CMAP and SNAP durations. The reduced amplitudes of mixed and sensory nerves might be due to decreased axonal number stimulation or actual decrease in number of axonal fibers, or defect at NMJ in non-diabetic obese. Prolonged durations but normal onset latencies and conduction velocities strongly suggest involvement of slow conducting fibers.

Reaction time in Stroop test in Nepalese Medical Students.

BACKGROUND: Stroop test is one of the widely used tests in cognitive psychology. It is used both in healthy population and also in patients to assess the selective attention. The selective attention as assessed by it is also found to be altered in bilinguals. In Nepal, most of the students are bilingual since most of the courses are in English language. Thus, they learn English language along with their native languages. This study is aimed to assess the selective attention in healthy Nepalese medical students. OBJECTIVE: To study the reaction time in stroop test in medical students of Nepal. MATERIALS AND METHODS: This study was conducted on 30 healthy male students aged 23.1±2.8 yrs. They were asked to read congruent (red printed in red ink) and incongruent (red printed in blue ink) tests in classical stroop cards. The reaction times for both the tests were calculated. Median with inter-quartile range was obtained for reaction time. Wilcoxon's Sign Rank Test was used to compare reaction time and errors between congruent and incongruent cards. RESULTS: The subjects took 82.10 (63.75-107.76) sec longer to read incongruent stroop test (p<0.001). The error made was 0 in congruent stroop test and 1.5 (0-3) in incongruent stroop test (p<0.001). No students made error in the congruent test but 60% (18) of students made error in incongruent test (p<.001) and interference percentage in incongruent was 157 (115.32-213.50)%. CONCLUSION: The reaction time and interferences were more in incongruent stroop test than congruent test. The interference was very high than that of previous literature's value. This indicates that Nepalese students have delayed attention while performing classical English version of stroop test.

Mild-to-moderate intensity exercise improves cardiac autonomic drive in type 2 diabetes.

AIMS/INTRODUCTION: The aim of the present study was to determine the effect of moderate aerobic exercise on cardiac autonomic function in type 2 diabetic patients. MATERIALS AND METHODS: Heart rate variability of 20 patients with type 2 diabetes was assessed. Resting electrocardiogram for the heart rate variability analysis at spontaneous respiration was recorded for 5 min in the supine position before and after 6 months of supervised aerobic training given three times per week. RESULTS: In time domain measures, the square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD; 29.7 [26-34.5] vs 46.4 [29.8-52.2] ms, P = 0.023) and the percentage of consecutive RR intervals that differ by more than 50 ms (pNN50; 10.7 [5.5-12.7] vs 26.1 [6.6-37.2]%, P = 0.025] were significantly increased after exercise. In frequency domain measures, low frequency (62.4 [59.1-79.2] vs 37 [31.3-43.3] nu, P = 0.003) and low frequency/high frequency (1.67 [1.44-3.8] vs 0.58 [0.46-0.59]%, P = 0.009) were significantly decreased, whereas high frequency (95 [67-149] vs 229 [98-427] ms(2), P = 0.006) and high frequency (37.6 [20.8-40.9] vs 63 [56.7-68.7] normalized units, P = 0.003) were significantly increased after exercise. In a Poincaré plot, standard deviation perpendicular to the line of the Poincaré plot (SD1; 21.3 [18.5-24.8]-33.1 [21.5-37.2] ms, P = 0.027) was significantly increased after exercise. CONCLUSIONS: These data suggest that three times per week moderate intensity aerobic exercise for 6 months improves cardiac rhythm regulation as measured by heart rate variability in type 2 diabetic patients.

Cardiovascular autonomic function and vibration perception threshold in type 2 diabetes mellitus.

OBJECTIVE: The aim of this study was to compare cardiovascular autonomic function tests (AFT) and vibration perception threshold (VPT) of patients with type 2 diabetes mellitus (T2DM) with controls. RESEARCH DESIGN/METHODS: The study was conducted on 60 diabetic patients comparing with 30 controls. The cardiovascular AFT and VPT were assessed in both groups. RESULTS: Among cardiovascular AFT, E:I ratio [1.24 (1.2-1.32) vs 1.3 (1.24-1.4), p=0.001], and Valsalva ratio [1.28 (1.22-1.4) vs 1.6 (1.5-1.73), p=0.001], the indicators of parasympathetic reactivity were reduced in T2DM. Rise in DBP during handgrip, an indicator of sympathetic reactivity was lower in T2DM [12 (10-14) vs 16 (14-18) mmHg, p=0.001] whereas, fall in SBP during head up tilt [4 (4-8) vs 5 (4-8) mmHg] was comparable. VPT (somatic sensation) was comparable between T2DM and control. CONCLUSION: Autonomic involvement is more marked than somatic, and parasympathetic involvement is more marked than the sympathetic, possibly reflecting severity and chronological pattern of their involvement.