F-wave records with submaximal stimulation: sustainability of the data and subject discomfort levels

Sangeeta Gupta, Ramji Singh


Background: F-wave studies are valuable electrodiagnostic tests with considerable roles in early diagnosis of diabetic neuropathy, detection of axonal neuropathies and focal proximal nerve dysfunctions. The recording of F-waves, however, requires recurrent supramaximal stimulation which entails subjects’ discomfort during the procedure. The present study hence attempted to assess the validity of the F-wave data obtained after submaximal stimulation thereby lessening the subject discomfort levels.

Methods: The study was conducted on 64 healthy subjects in the age-group of 18-40 years with normal neurological examinations. F responses from median, ulnar, tibial and peroneal nerves by both supramaximal and submaximal stimulation were recorded. Subjects rated discomfort level on a visual analogue scale. Mean values of F-wave minimum latency, mean latency, mean duration, persistence, chronodispersion, F/M amplitude ratio and subject’s discomfort level obtained by the two techniques were compared by paired t-test. P value <0.05 was considered as statistically significant.

Results: Mean values of F-wave mean latency, minimum latency, chronodispersion and stimulus duration were not found to be statistically significantly different in the groups (p>0.05). Mean persistence, mean F/M amplitude ratio and mean subject discomfort levels varied statistically significantly.

Conclusions: F-wave data can be attained by submaximal stimulation. F-wave mean and minimum latency, chronodispersion and duration remain relatively stable, but more stimuli may be needed for accurate values. For F/M amplitude ratio and F-wave persistence, submaximal reference range would be required. Nonetheless, diminution in subject discomfort with valid F-wave latency values, favours low intensity stimulation.


F-wave, Latency, Stimulation, Submaximal, Supramaximal

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Fisher, M.A. F-wave studies: clinical utility. Muscle Nerve. 1998;27:1098-101.

Andersen H, Stålberg E, Falck B. F-wave latency, the most sensitive nerve conduction parameter in patients with diabetes mellitus. Muscle Nerve. 1997;20(10):1296-302.

Li Z, Hu X, Tang N. Significance of neuroelectrophysiological tests in the early diagnosis of sub-clinical neuropathy with diabetes mellitus. J Huazhong Univ Sci Technolog Med Sci. 2006;26(4):429-31.

Jerath NU, Aul E, Reddy CG, Azadeh H, Swenson A, Kimura J. Prolongation of F-wave minimal latency: a sensitive predictor of polyneuropathy Int J Neurosci. 2015;126(6):1-13.

Kohara N, Kimura J, Kaji R, Goto Y, Ishii J. Multicenter analysis on intertribal variability of nerve conduction studies: healthy subjects and patients with diabetic neuropathies. In: Kimura J, Shibishaski H, eds. Recent Advances in Clinical Neurophysiology. Amsterdam: Elsevier; 1996:809-815.

Eisen A, Fisher MA. Recommendations for the practice of clinical neurophysiology: guidelines of the International Federation of Clinical Neurophysiology. Electroencephalogr Clin Neurophysiol Suppl. 1999;52:255-7.

Dressnandt J, Auer C, Conrad B. Influence of baclofen upon the alpha-motoneuron in spasticity by means of F-wave analysis. Muscle Nerve. 1995;18(1):103-7.

Mebrahtu S, Rubin M. The utility of F wave chronodispersion in lumbosacral radiculopathy. J Neurol. 1993;240(7):427-9.

Fisher MA. H-Reflex and F-Response Studies. In: Aminoff MJ, editor, Aminoff’s Electrodiagnosis in Clinical Neurology, 6th edn. Saunders Elsevier; 2012:407-420.

Fisher MA, Zhu JQ, Uddin MK, Grindstaff P. Submaximal stimulation and f-wave parameters. J Clin Neurophysiol. 2008;25(5):299-03.

Kong X, Bansal P, Megerian JT, Gozani SN. Peroneal F-wave characteristics under submaximal stimulation. Neurol Neurophysiol Neurosci. 2006:1.

DiBenedetto M, Gale SD, Adarmes D, Schabacker M. F-wave acquisition using low-current stimulation. Muscle Nerve. 2003;28(1):82-6.

Streiner DL, Norman GR. Health measurement scales: a practical guide to their development and use. 5th edn. New York: Oxford University Press; 1989.

Toyokura M. F-wave duration in diabetic polyneuropathy. Muscle Nerve. 1998; 21:246-9.

Toyokura M, Furukawa T. F wave duration in mild S1 radiculopathy: comparison between the affected and unaffected sides. Clin Neurophysiol. 2002;113:1231-5.

Cornwall MW, Nelson C. Median nerve F-wave conduction in healthy subjects. Phys Ther. 1984;64(11):1679-83.

Parmar L, Archana Singh. The study of F-waves in normal healthy individuals. Internet J Neurol. 2013;16:1-8.

Mohsen SS, Hamdan FB, Mohammed NH. Measurement of F wave components in a sample of healthy Iraqis: normative data. Saudi J Health Sci. 2013;2:194-201.

Subedi P, Limbu N, Thakur D, Khadka R, Gupta S. The F waves study in young healthy individuals. Int J Res Med Sci. 2018;6:1628-31.

Kimura J, Yanagisawa H, Yamada T, Mitsudome A, Sasaki H, Kimura A. Is the F wave elicited in a select group of motoneurons? Muscle Nerve. 1984;7:392-9.

Chroni E, Panayiotopoulos CP. The importance of sample size for the estimation of F wave latency parameters in the ulnar nerve. Muscle Nerve. 1994;17:1480-3.

Fisher MA, Hoffen B, Hultman C. Normative F-wave values and the number of recorded F-waves. Muscle Nerve. 1994;17:1185-9.

Panayiotopoulos CP, Chroni E. F-waves in clinical neurophysiology: a review, methodological issues and overall value in peripheral neuropathies. Electroenceph Clin Neurophysiol. 1996;101:365-74.

Raudino F. F-wave: sample size and normative values. Electromyogr Clin Neurophysiol. 1997;37:107-9.