Abstract
Human physiological tremor is a complex phenomenon that is modulated by numerous mechanical, neurophysiological, and environmental conditions. Researchers investigating tremor have suggested that acute hypoxia increases tremor amplitude. Based on the results of prior studies, we hypothesized that human participants exposed to a simulated altitude of 4,500 m would display an increased tremor amplitude within the 6–12 Hz frequency range. Postural and kinetic tremors were recorded with a laser system in 23 healthy male participants before, during, and after 1 h of altitude-induced hypoxia. A large panel of tremor characteristics was used to investigate the effect of hypoxia. Acute hypoxia increased tremor frequency content between 6 and 12 Hz during both postural and kinetic tremor tasks (P < 0.05, F = 6.142, Eta2 = 0.24 and P < 0.05, F = 3.767 Eta2 = 0.14, respectively). Although the physiological mechanisms underlying the observed changes in tremor are not completely elucidated yet, this study confirms that acute hypoxia increases tremor frequency in the 6–12 Hz range. Furthermore, this study indicates that changes in physiological tremor can be detected at lower hypoxemic levels than previously reported (blood saturation in oxygen = 80.9%). The effects of hypoxia mainly result from a cascade of events starting with the activation of the hypothalamic–pituitary–adrenal axis causing in turn an increase in catecholamine release, leading to an augmentation of tremor amplitude in the 6- to12-Hz interval and heart rate increase.
Similar content being viewed by others
Notes
Please note that the description of the quantification of the changes in terms of ‘better or worse performance’ regarding tremor characteristics is stated here as an indication only. Though they could be adapted in describing pathological tremor such characterizations would be too speculative to be used to fully describe tremor staying within the physiological range
References
Arihara M, Sakamoto K (1999) Contribution of motor unit activity enhanced by acute fatigue to physiological tremor of finger. Electromyogr Clin Neurophysiol 39:235–247
Bartholomew CJ, Jensen W, Petros TV et al (1999) The effect of moderate levels of simulated altitude on sustained cognitive performance. Int J Aviat Psychol 9:351–359
Beuter A, Edwards R (1998) Tremor in Cree subjects exposed to methylmercury: a preliminary study. Neurotoxicol Teratol 20:581–589
Beuter A, Edwards R (1999) Using frequency domain characteristics to discriminate physiologic and parkinsonian tremors. J Clin Neurophysiol 16:484–494
Beuter A, Edwards R (2002) Characterization and discrimination of kinetic tremor in Parkinson’s disease. Rev Neurol (Paris) 158:338–340
Beuter A, Edwards R, Lamoureux D (2000) Neuromotor profiles: what are they and what can we learn from them? Brain Cogn 43:39–44
Bonvallet M, Audisio M, Hugelin A (1959) Reticular and cortical factors in the changes in motoneuron excitability seen during acute hypoxia. J Physiol (Paris) 51:411–412
Britton TC, Gresty MA (1992) Mechanisms for essential tremor. Lancet 340:610
Britton TC, Thompson PD (1995) Primary orthostatic tremor. BMJ 310:143–144
Chalmers JP, Korner PI, White SW (1966) The control of the circulation in skeletal muscle during arterial hypoxia in the rabbit. J Physiol 184:698–716
Cotes JE, Chinn DJ, Miller MR (2006) Lung function: physiology, measurement and application in medicine. Blackwell, Victoria
Deuschl G, Bain P, Brin M (1998) Consensus statement of the movement disorder society on tremor. Ad Hoc Scientific Committee. Mov Disord 13(Suppl 3):2–23
Deuschl G, Raethjen J, Lindemann M et al (2001) The pathophysiology of tremor. Muscle Nerve 24:716–735
Edwards R, Beuter A (2000) Using time domain characteristics to discriminate physiologic and parkinsonian tremors. J Clin Neurophysiol 17:87–100
Elble RJ (1986) Physiologic and essential tremor. Neurology 36:225–231
Elble RJ (1996) Central mechanisms of tremor. J Clin Neurophysiol 13:133–144
Elble RJ, Koller WC (1990) Tremor. The John Hopkins University press, London
Fellows IW, Macdonald IA, Wharrad HJ et al (1986) Low plasma concentrations of adrenaline and physiological tremor in man. J Neurol Neurosurg Psychiatry 49:396–399
Ganong WF (2001) Review of medical physiology. McGraw-Hill, New York
Goodman D, Kelso JA (1983) Exploring the functional significance of physiological tremor: a biospectroscopic approach. Exp Brain Res 49:419–431
Gross J, Timmermann L, Kujala J et al (2002) The neural basis of intermittent motor control in humans. Proc Natl Acad Sci USA 99:2299–2302
Hallett M (1991) Classification and treatment of tremor. JAMA 266:1115–1117
Hiramatsu Y, Takahashi H, Izumi A (1971) Effect of inosine on adrenaline and vasopressin induced myocardial hypoxia. Jpn J Pharmacol 21:355–360
Hugelin A, Bonvallet M, Dell P (1959) Reticular & cortical activation of chemoreceptor origin during hypoxia. Electroencephalogr Clin Neurophysiol Suppl 11:325–340
Koller W, Cone S, Herbster G (1987) Caffeine and tremor. Neurology 37:169–172
Koster B, Lauk M, Timmer J et al (1998) Central mechanisms in human enhanced physiological tremor. Neurosci Lett 241:135–138
Krause WL, Leiter JC, Tenney MS et al (2000) Acute hypoxia activates human 8–12 Hz physiological tremor. Respir Physiol 123:131–141
Lakie M, Frymann K, Villagra F et al (1994a) The effect of alcohol on physiological tremor. Exp Physiol 79:273–276
Lakie M, Walsh EG, Arblaster LA et al (1994b) Limb temperature and human tremors. J Neurol Neurosurg Psychiatry 57:35–42
Legros A, Beuter A (2005) Effect of a low intensity magnetic field on human motor behavior. Bioelectromagnetics 26:657–669
Legros A, Gaillot P, Beuter A (2006) Transient effect of low-intensity magnetic field on human motor control. Med Eng Phys 28:827–836
Li XY, Wu XY, Fu C et al (2000) Effects of acute mild and moderate hypoxia on human mood state. Space Med Med Eng (Beijing) 13:1–5
Lippold OC (1970) Oscillation in the stretch reflex arc and the origin of the rhythmical, 8–12 C-S component of physiological tremor. J Physiol 206:359–382
Lippold O (1981) The tremor in fatigue. Ciba Found Symp 82:234–248
Llinas R, Volkind RA (1973) The olivo-cerebellar system: functional properties as revealed by harmaline-induced tremor. Exp Brain Res 18:69–87
Marsden CD, Meadows JC (1970) The effect of adrenaline on the contraction of human muscle. J Physiol 207:429–448
Marsden CD, Meadows JC, Lange GW et al (1967) Effect of deafferentation on human physiological tremor. Lancet 2:700–702
Marsden CD, Meadows JC, Lange GW et al (1969) The role of the ballistocardiac impulse in the genesis of physiological tremor. Brain 92:647–662
Mazzocchio R, Gelli F, Del Santo F et al (2008) Effects of posture-related changes in motor cortical output on central oscillatory activity of pathological origin in humans. Brain Res 1223:65–72
McAuley JH, Marsden CD (2000) Physiological and pathological tremors and rhythmic central motor control. Brain 123(Pt 8):1545–1567
Morrison S, Kavanagh J, Obst SJ et al (2005) The effects of unilateral muscle fatigue on bilateral physiological tremor. Exp Brain Res 167:609–621
Nelson M (1982) Psychological testing at high altitudes. Aviat Space Environ Med 53:122–126
Norman KE, Edwards R, Beuter A (1999) The measurement of tremor using a velocity transducer: comparison to simultaneous recordings using transducers of displacement, acceleration and muscle activity. J Neurosci Methods 92:41–54
Pavlicek V, Schirlo C, Nebel A et al (2005) Cognitive and emotional processing at high altitude. Aviat Space Environ Med 76:28–33
Peterson BS, Skudlarski P, Gatenby JC et al (1999) An fMRI study of Stroop word-color interference: evidence for cingulate subregions subserving multiple distributed attentional systems. Biol Psychiatry 45:1237–1258
Pickles H, Perucca E, Fish A et al (1981) Propranolol and sotalol as antagonists of isoproterenol-enhanced physiologic tremor. Clin Pharmacol Ther 30:303–310
Pollok B, Gross J, Dirks M et al (2004) The cerebral oscillatory network of voluntary tremor. J Physiol 554:871–878
Scow J, Krasno LR, Ivy AC (1950) The immediate and accumulative effect on psychomotor performance of exposure to hypoxia, high altitude and hyper-ventilation. J Aviat Med 21:79–81
Stein RB, Lee RG, Nichols TR (1978) Modifications of ongoing tremors and locomotion by sensory feedback. Electroencephalogr Clin Neurophysiol, suppl 5, pp 12–519
Stiles RN, Randall JE (1967) Mechanical factors in human tremor frequency. J Appl Physiol 23:324–330
Travis LE (1929) The relation of voluntary movement to tremors. J Exp Psychol 12:515–524
Vaillancourt DE, Newell KM (2000) Amplitude changes in the 8–12, 20–25, and 40 Hz oscillations in finger tremor. Clin Neurophysiol 111:1792–1801
Vallbo AB, Wessberg J (1993) Organization of motor output in slow finger movements in man. J Physiol 469:673–691
van der Post J, Noordzij LA, de Kam ML et al (2002) Evaluation of tests of central nervous system performance after hypoxemia for a model for cognitive impairment. J Psychopharmacol 16:337–343
Vetter K, Horvath SM (1961) Analysis of physiological tremor during rest and exhaustion. J Appl Physiol 16:994–996
Virues-Ortega J, Buela-Casal G, Garrido E et al (2004) Neuropsychological functioning associated with high-altitude exposure. Neuropsychol Rev 14:197–224
Virues-Ortega J, Garrido E, Javierre C et al (2006) Human behaviour and development under high-altitude conditions. Dev Sci 9:400–410
Wachs H, Boshes B (1966) Tremor studies in normals and parkinsonism. Arch Neurol pp 66–82
Watson JM, Richens A (1974) The effects of salbutamol and terbutaline on physiological tremor, bronchial tone and heart rate. Br J Pharmacol 1:223–227
Wessberg J, Vallbo AB (1996) Pulsatile motor output in human finger movements is not dependent on the stretch reflex. J Physiol 493(Pt 3):895–908
Acknowledgments
We would like to thank Mr. John Patrick for his help in conducting the experiment, Mr. Michael Corbacio for his assistance with LabView and Matlab programming, and Mr. Lynn Keenliside for his technical contributions and expertise. This work was funded in-part by Defence Research and Development Canada, the Canadian Institutes of Health Research, the Natural Sciences and Engineering Research Council of Canada, the Ontario Research Fund and the Canadian Foundation for Innovation.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Susan Ward.
Appendix
Appendix
Characteristics computed on tremor time series Footnote 1
- Amplitude:
-
Root Mean Square of the filtered position time series centered on their mean. Computed on position data filtered between 2 (3 for kinetic tremor) and 20 Hz. Larger values correspond to worse performance
- Drift:
-
Quantifies the amplitude of the drift of the finger (slow movements with frequencies <0.1 Hz). Computed on position data only in the postural tremor condition. Larger values correspond to worse performance
- Median frequency:
-
Computed on tremor velocity power spectrum between 2 (3 for kinetic tremor) and 20 Hz. Determines the value at which 50% of the power is below this frequency and 50% is above. Smaller values usually correspond to worse performance
- Amplitude fluctuations:
-
Characterizes the variability of tremor amplitude over time. It is the standard deviation of the envelope around tremor oscillations. Computed on position data. Larger values correspond to worse performance
- Frequency concentration:
-
Computed on tremor velocity power spectrum between 2 and 20 Hz. Quantifies the degree of organization of tremor by computing the width of the interval containing 68% of the power of the spectrum between 2 (3 for kinetic tremor) and 20 Hz. Smaller values correspond to worse performance
- Proportional power in 2–4 Hz range:
-
Computed on tremor velocity power spectrum between 2 and 20 Hz. Proportion of the power contained in this range compared with the spectrum between 2 (3 for kinetic tremor) and 20 Hz. Larger values usually correspond to worse performance
- Proportional power in 4–6 Hz range:
-
Computed on tremor velocity power spectrum between 2 and 20 Hz. Proportion of the power contained in this range compared with the spectrum between 2 (3 for kinetic tremor) and 20 Hz. Larger values usually correspond to worse performance
- Proportional power in 6–12 Hz range:
-
Computed on tremor velocity power spectrum between 2 (3 for kinetic tremor) and 20 Hz. Proportion of the power contained in this range compared with the spectrum between 2 (3 for kinetic tremor) and 20 Hz. Smaller values usually correspond to worse performance
- Mean Power in the 6–12 Hz range:
-
Computed on tremor velocity power spectrum between 2 (3 for kinetic tremor) and 20 Hz. Average of the power contained in this frequency range. It is the range containing the physiological tremor components. Computed on velocity data filtered between 2 (3 for kinetic tremor) and 20 Hz. Larger values correspond to worse performance
- Proportional power in 12–20 Hz range:
-
Computed on tremor velocity power spectrum between 2 and 20 Hz. Proportion of the power contained in this range compared with the spectrum between 2 (3 for kinetic tremor) and 20 Hz. Larger values usually correspond to worse performance
- Mean tracking error:
-
Mean of the absolute difference between the finger position and the reference position during a recording. Computed on position data filtered between 3 and 20 Hz. Larger values correspond to worse performance
- Delay:
-
Average delay between the displacement of the target on the screen and the displacement of the subject’s index finger. Computed on position data filtered between 3 and 20 Hz. Larger values correspond to worse performance.
Rights and permissions
About this article
Cite this article
Legros, A., Marshall, H.R., Beuter, A. et al. Effects of acute hypoxia on postural and kinetic tremor. Eur J Appl Physiol 110, 109–119 (2010). https://doi.org/10.1007/s00421-010-1475-x
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00421-010-1475-x