Abstract
Using a multi-electrode nerve-signal recording cuff and a method of signal processing described previously, activity in axons with different propagation velocities can be distinguished, and the relative amplitude of the small-fibre signals increased. This paper is, largely, an analysis of the selectivity and noise of this system though impedance measurements from an actual cuff are included. The signal processor includes narrow band-pass filters. It is shown that the selectivity and noise both increase with the centre frequencies of these filters. A convenient approach is to make the filter frequencies inversely related to the artificial time delays so that the filter ‘Q’s are approximately constant and the noise densities are equal for all velocity filters. Numerical calculations, using formulae for this system and for the conventional tripole, based on a fixed cuff size and tissue resistivity, find the number of action potentials per second that must pass through the cuff so that the signal power equals the noise power. For slow fibres (20 m/s), the rate is 14 times lower for the multi-electrode cuff than the tripole, a significant advantage for recording from these fibres.
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Abbreviations
- A, B, C :
-
constants of TMAP function (Eq. 2)
- DSP:
-
digital signal processor
- v :
-
velocity of action potentials (AP)
- V AO :
-
voltage spectrum at the adder output (AO)
- V m :
-
voltage spectrum of the trans-membrane action potential (TMAP)
- H 0 :
-
transfer function of the tripole
- G :
-
transfer function of the delay-&-add
- d :
-
electrode pitch
- R s :
-
spreading resistance of one electrode
- R e :
-
axial resistance through the cuff between the end electrodes
- L e :
-
axial distance through the cuff between the end electrodes
- N :
-
number of tripoles in the multi-electrode cuff (MEC)
- τ :
-
artificial time delay (Fig. 1)
- v0, v+, v−:
-
centre, higher −3 dB, and lower −3 dB velocities of the velocity-selective filter
- Q v :
-
Q-factor for filter where \( Q_{v} = \frac{{v_{0} }}{{v_{ + } - v_{ - } }} \)
- α, β, γ :
-
fractions of noise added after delays (Eq. 14)
- P :
-
power spectral density (PSD)
- E :
-
energy spectral density (ESD)
- TAO:
-
tripolar amplifier output
- k :
-
Boltzmann’s constant (1.38 × 10−23 J/K)
- T :
-
absolute temperature
- G 1, G 2 :
-
gains of first- and second-rank amplifiers A1 and A2 (Fig. 5)
- n :
-
index for elements in Fig. 5
- Ψ :
- SNR:
-
signal-to noise ratio after the bandpass filters (BPF)
- SPU:
-
signal processing unit (see Fig. 1)
- BPF:
-
bandpass filter (always narrow in this paper)
- f :
-
frequency equivalent to ω/(2π)
- r :
-
average action potential rate (AP/s), from all fibres in appropriate range of velocity
- f1, f2:
-
band edges of wide-band tripole amplifier (500 and 5,000 Hz here)
References
Andreasen LN, Struijk JJ (2006) Model-based evaluation of the short-circuited tripolar cuff configuration. Med Biol Eng Comput 44(5):404–413. doi:10.1007/s11517-006-0057-x
Bronstein IN, Semendjajew KA (1989) Taschenbuch der Mathematik, 24th edn. Teuber Verlagsgesellschaft Leipzig
Donaldson PEK, Donaldson NN, Rushton DN, Perkins TA (1998) Estimated electrode operating conditions of the first London Mk V implanted stimulator. J Med Eng Technol 22:216–219
Donaldson NN, Zhou L, Perkins TA, Munih M, Haugland M, Sinkjaer T (2003) Implantable telemeter for long term electroneurographic recordings in animals and man. Med Biol Eng Comput 41:654–664. doi:10.1007/BF02349973
Grill WM, Mortimer JT (1994) Electrical properties of implant encapsulation tissue. Ann Biomed Eng 22:23–33. doi:10.1007/BF02368219
Hoffer JA, Marks WB, Rymer WZ (1974) Nerve fiber activity during normal movements. Proceedings of the annual meeting for society of neuroscience, St Louis, 4, pp 300
Inmann A, Haugland M (2004) Implementation of natural sensory feedback in a portable control system for a hand grasp neuroprosthesis. Med Eng Phys 26(6):449–458. doi:10.1016/j.medengphy.2004.03.003
Jia X, Koenig MA, Zhang X, Zhang J, Chen T, Chen Z (2007) Residual motor signal in long-term human severed peripheral nerves and feasibility of neural signal-controlled artificial limb. J Hand Surg Am 32(5):657–666. doi:10.1016/j.jhsa.2007.02.021
Liu X, Demosthenous A, Donaldson N. Platinum electrode noise in the ENG spectrum. Parallel submission to Med Biol Eng Comput. doi:10.1007/s11517-008-386-z
Matthews PBC (1972) Mammalian muscle receptors and their central actions. Edward Arnold, London
Navarro X, Krueger TB, Lago N, Micera S, Stieglitz T, Dario P (2005) A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems. J Peripher Nerv Syst 10(3):229–258. doi:10.1111/j.1085-9489.2005.10303.x
Rieger R, Taylor J, Demosthenous A, Donaldson N, Langlois PJ (2003) Design of a low-noise preamplifier for nerve cuff electrode recording. IEEE J Solid-State Circuits 38:1373–1379. doi:10.1109/JSSC.2003.814437
Schuettler M, Stieglitz T, Gross M, Altpeter D, Staiger A, Doerge T, et al. (2001) Reducing stiffness and electrical losses of high channel hybrid nerve cuff electrodes CD-ROM Proc. 23th Annual international conference of the IEEE. EMBS, Istanbul, 25–28 October 2001
Schuettler M, Seetohul V, Taylor J, Donaldson N (2006) Velocity-selective recording from frog nerve using a multi-contact cuff electrode. Conf Proc IEEE Eng Med Biol Soc 1:2962–2965
Stein RB, Charles D, Davis L, Jhamandas J, Mannard A, Nichols TR (1975) Principles underlying new methods for chronic neural recording. Can J Neurol Sci 2(3):235–244
Struijk JJ (1997) The extracellular potential of a myelinated nerve fibre in an unbounded medium and in nerve cuff models. Biophys J 72:2457–2469
Taylor J, Donaldson N, Winter J (2004) The use of multiple-electrode nerve cuffs for low velocity and velocity-selective neural recording. Med Biol Eng Comput 42(5):634–643. doi:10.1007/BF02347545
Rieger R, Schuettler M, Pal D, Clarke C, Langlois P, Taylor J et al (2006) Very low-noise ENG amplifier system using CMOS technology. IEEE Trans Neural Syst Rehabil Eng 14(4):427–437. doi:10.1109/TNSRE.2006.886731
Triantis IF, Demosthenous A, Donaldson N (2005) On cuff imbalance and tripolar ENG amplifier configurations. IEEE Trans Biomed Eng 52(2):314–320. doi:10.1109/TBME.2004.840470
Upshaw BM (1999) PhD Thesis, University of Aalborg, Denmark
Acknowledgments
We thank the UK EPSRC (Grant GR/S93790/01) and the CEU (IMANE STREP 026602) for supporting this work; and also the German Academic Exchange Service (DAAD) for M. Schuettler’s fellowship.
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Donaldson, N., Rieger, R., Schuettler, M. et al. Noise and selectivity of velocity-selective multi-electrode nerve cuffs. Med Biol Eng Comput 46, 1005–1018 (2008). https://doi.org/10.1007/s11517-008-0365-4
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DOI: https://doi.org/10.1007/s11517-008-0365-4