Table of Contents

2016 Month : December Volume : 2 Issue : 2 Page : 3-5

EFFECT OF LIMB DOMINANCE ON PERIPHERAL SENSORY NERVE CONDUCTION VELOCITY.

Soumya B. A1, Vikas A. Reddy2, D. V. Deshpande3

1Assistant Professor, Department of Physiology, S. S. Institute of Medical Sciences and Research Centre, Davangere.
2MBBS Student, S. S. Institute of Medical Sciences and Research Centre, Davangere.
3Professor and HOD, S. S. Institute of Medical Sciences and Research Centre, Davangere.

Corresponding Author:
Dr. Soumya B. A,
Assistant Professor,
Department of Physiology,
S. S. Institute of Medical Sciences and Research Centre,
Davangere.
E-mail: soumya.ba@gmail.com

ABSTRACT

BACKGROUND

Nerve Conduction Study is a pure physiological measure of the speed with which the electrical impulses are transmitted along the peripheral nerve fibres and across synapses, involving no cognitive activity. Various anatomic and physiologic factors affecting the conduction velocity of the nerve are well studied except handedness, which could be the probable reason behind disproportionately large number of artists, musicians and mathematicians being left-handers. Hence, the study was undertaken to evaluate the Nerve Conduction Velocity taking handedness aspect into consideration.

 

MATERIALS AND METHODS

The study was done in accordance with the Institutional Ethical Committee standards. The study included 100 medical students (10 left handers and rest right handers) in the age group 17–21 years. Sensory Nerve Conduction Velocity (NCV) of median and ulnar nerves on both the sides were recorded using RMSEMGEPMK2 software Equipment. Stimulation was done using standard supramaximal technique using a square wave pulse of 0.1 ms duration, distance measured by metal tape and velocity calculated. Results were expressed as Mean ± S.D. For comparisons between the groups (right and left handers), Student’s unpaired ‘t’ test was used and a p value of less than 0.05 considered as significant.

RESULTS

Sensory nerve conduction velocities (in metres per second) of median and ulnar nerves of both the sides in left-handed individuals were higher compared to their right-handed counterparts. But this difference was significant in the ulnar nerve (p=0.012).

CONCLUSION

The study concludes that the left-handed individuals have faster sensory nerve conduction velocity compared to right handers.

KEYWORDS

Handedness, Nerve Conduction Velocity, Limb Dominance.

How to cite this article

Soumya BA, Reddy VA, Deshpande DV. Effect of limb dominance on peripheral sensory nerve conduction velocity. Journal of Evolution of Research in Human Physiology 2016; Vol. 2, Issue 2, July-December 2016; Page:3-5.

BACKGROUND

The economic, social and personal burden of common neurological disorders have been the subject of intense study all over the world.1 The widespread interest in disorders of peripheral nervous system, which has burgeoned in recent years, primarily has its origin in the introduction of new investigating techniques.2 With the advent of newer technologies there has been a tremendous increase in the number of patients with nerve disorders.3 Nerve Conduction Study is a part of electrodiagnostic procedure that helps in establishing the type and extent of the abnormality of the nerves.4

Nerve Conduction Study is a pure physiological measure of the speed with which the electrical impulses are transmitted along the peripheral nerve fibres and across synapses, involving no cognitive activity.5 The conduction velocity of the nerve depends on anatomical factors such as the fibre diameter, degree of myelination and the internodal distance.6

Other factors such as age, temperature, height, gender and limb are the well-known physiological variables affecting Nerve Conduction Study.7 The effect of handedness on nerve conduction is not known much and needs further evaluation.

Cerebral dominance is a known fact and has its effect in terms of speech, handedness, facial recognition, etc. Lateralisation of nerve conduction velocity is also expected.

Disproportionately, large number of artists, musicians and mathematicians are left-handers.8 So far, not much data has been collected on motor Nerve Conduction Velocity taking handedness aspect into consideration. Hence, this study is undertaken to observe if any difference in limb dominance translates into difference in nerve conduction velocity, which will have far reaching real life implications.

 

MATERIALS AND METHODS

The study titled “Effect of limb dominance on peripheral sensory nerve conduction velocity” was conducted in the Department of Physiology, SSIMS & RC, Davangere. This study included 100 young medical students (10 left handers and rest were right handers) of both the genders in the age group 17–21 years. Those individuals using their left hand either for dexterity or strength or both were labelled as left handers. After taking a detailed written informed consent, preliminary details with complete history was recorded. The study was done in accordance with the Institutional Ethical Committee Standards.

Exclusion Criteria

Peripheral nerve injury, metabolic disorders, fracture, deformity, radiculopathy, nerve compression, neurological disorder, intake of drugs, or any addictions.

Subjects were called in the morning after light breakfast to get acclimatised in an air-conditioned room (21–23o C) for 15 minutes. Sensory Nerve Conduction Velocity (NCV) of median and ulnar nerves on both the sides were recorded using RMSEMGEPMK2 software equipment. Stimulation was done using standard supramaximal technique using a square wave pulse of 0.1 ms duration, distance to be measured by metal tape and velocity calculated.

Statistical Analysis

Results were expressed as mean±S.D. For comparisons between the groups (Right and left handers), Student’s unpaired‘t’ test was used and a p value of less than 0.05 considered as significant.

RESULTS

A total of 100 subjects (10 left handers & 90 right handers) were included in the study. The mean age (in years) was 20 in left handers and 19.73 in right handers. There was no significant difference in the age in the two groups (p = 0.474) (Graph-1). Gender wise comparisons showed no significant difference between the two groups (Graph-2).

Mean height (in centimetres) was 170.20 in left handers and 169.76 in right handers with no significant difference. Mean weight (in kilograms) was 71.10 in left handers and 66.37 in right handers with no significant difference              (Graph-3).

 

Comparison of Nerve Conduction Velocity

Sensory nerve conduction velocities (in metres per second) of median and ulnar nerves of both the sides in left-handed individuals were higher compared to their right-handed counterparts.

But this difference was significant only in the ulnar nerve (p=0.012) (Table-1, Graph-4).

Sensory Nerve Conduction Velocity

 

Handedness

 

Left Handed

Right Handed

P- value

No. of Cases

Mean±S.D

No. of Cases

Mean ± S.D

Left median

 nerve

10

56.24±6.12

90

54.87±6.07

.522

Left ulnar

nerve

10

54.30±7.13

90

47.76±7.86

.012

 

Right median nerve

10

54.02±4.10

90

53.58±9.73

.890

Right ulnar nerve

10

52.11±5.92

90

50.39±6.49

.416

Table 1. Comparison of Sensory Nerve Conduction Velocity in Right and Left Handers

 

Graph 1. Comparison of Age in Right and Left Handers


Graph 2. Comparison of Gender in Right and Left Handers


Graph 3. Comparison of Height & Weight

In Right and Left Handers


Graph 4. Comparison of Sensory Nerve Conduction Velocity in Right and Left Handers


DISCUSSION

The subjects selected for our study belonged to the age group of 17–21 years. As the study was carried out in a laboratory at constant temperature, the results cannot be attributed to variations in temperature. Krishnamurthy et al demonstrated that there is no influence of sex on nerve conduction.9

The human nervous system adapts to the functional requirements with considerable plasticity depending on the use, the physiological characteristics and response changes. In the past decade, several researchers reported differences in physiology between the dominant and the nondominant upper limb.10

In this study, we report a higher sensory nerve conduction velocity in left handers compared to right handers with a significant difference in the left ulnar nerve. Other sensory nerve conduction velocities were also higher in left handers though not significant. Asymmetry of sensory nerve conduction velocity was also detected by Bromberg et al.11 Higher sensory nerve conduction velocities in left handers may be because of genetic reasons and this may contribute to functional differences during growth in early childhood.

Similar results were also reported by earlier studies like Gupta et al1 and Tayade et al.6

 

CONCLUSION

The study concludes that the left-handed individuals have faster sensory nerve conduction velocity compared to right handers. Further, this difference should be taken into account before making any neurological diagnosis in left handers.

Though this study is by no means exhaustive, it does provide a glimpse of the differences between the sensory nerve conduction velocity in left and right handers. Further research is necessary to deduce a definite relationship between NCV and cognitive parameters such as the Intelligence Quotient.

 

Acknowledgement

Acknowledgement: our sincere regards to ICMR for this Research Study.

 

Suggestions

Individual differences in intelligence could be viewed as being to some degree attributable to differences in the speed and efficiency with which neurophysiological processes occur.

Peripheral NCV is considerably easier and less expensive measure than many of the previously investigated physiological correlates of intelligence such as cerebral blood flow and cerebral glucose metabolic rate. Results from our study provides input to further studies on human intelligence and handedness to provide an understanding of the biological basis of the individual differences in intelligence and mental abilities with reference to limb dominance.

 

REFERENCES

  1. Gupta N, Sanyal S, Babbar R. Sensory nerve conduction velocity is greater in left handed persons. Indian J Physiol Pharmacol 2008;52(2):189-92.
  2. Singh HJ, Arora R. The comparison of the motor nerve conduction velocity in the left and right upper limbs in normal right handed subjects. Journal of Clinical and Diagnostic Research 2011;5(2):269-70.
  3. Sathiamoorthy A, Sathiamoorthy SS. Limb dominance and motor conduction velocity of median and ulnar nerves. Indian J Physiol Pharmacol 1990;34(1):51-3.
  4. Misra UK, Kalita J. Nerve conduction study. In: Misra UK, Kalita J(eds). Clinical Neurophysiology. New Delhi, Elsevier 1999:25-8.
  5. Vernon PA, Mori M. Intelligence, reaction times and peripheral nerve conduction velocity. Intelligence 1992;16(3-4):273-88.
  6. Tayade MC, Latti RG. Effect of limb dominance on nerve conduction studies in healthy subjects. Pravara Med Rev 2011;3(2):31-3.
  7. Bhorania S, Ichaporia RB. Effect of limb dominance on motor nerve conduction. Indian J Physiol Pharmacol 2009;53(3):279-82.
  8. Wright L, Hardie SM, Rodway P. Pause before you respond: handedness influences response style on the tower of Hanoi task. Laterality 2004;9(2):133-47.
  9. Krishnamurthy N, Susheela V, Kishan S, et al. The standardized distal motor latency and the peak to peak amplitudes of evoked potentials in the extremities of humans. Ind J Physiol Pharmacol 1988;32:51-5.
  10. Kamen G, Greenstein SS, DeLuca CJ. Lateral dominance and motor unit firing behavior. Brain Research 1992;576(1):165-7.
  11. Bromberg MB, Jaros L. Symmetry of normal motor and sensory nerve conduction measurements. Muscle Nerve 1998;21(4):498-503.




 



 

Videos :

watch?v

Download Download [ PDF ] Download[ ABSTRACT ] Email Send to a friend