A Methodology for Detecting Field Potentials from the External Ear Canal: NEER and EVestG

An algorithm called the neural event extraction routine (NEER) and a method called Electrovestibulography (EVestG) for extracting field potentials (FPs) from artefact rich and noisy ear canal recordings is presented. Averaged FP waveforms can be used to aid detection of acoustic and or vestibular pathologies. FPs were recorded in the external ear canal proximal to the ear drum. These FPs were extracted using an algorithm called NEER. NEER utilises a modified complex Morlet wavelet analysis of phase change across multiple scales and a template matching (matched filter) methodology to detect FPs buried in noise and biological and environmental artefacts. Initial simulation with simulated FPs shows NEER detects FPs down to −30 dB SNR (power) but only 13–23% of those at SNR’s <−6 dB. This was deemed applicable to longer duration recordings wherein averaging could be applied as many FPs are present. NEER was applied to detect both spontaneous and whole body tilt evoked FPs. By subtracting the averaged tilt FP response from the averaged spontaneous FP response it is believed this difference is more representative of the vestibular response. Significant difference (p < 0.05) between up and down whole body (supine and sitting) movements was achieved. Pathologic and physiologic evidence in support of a vestibular and acoustic origin is also presented.

[1]  W. Abend,et al.  Response to static tilts of peripheral neurons innervating otolith organs of the squirrel monkey. , 1972, Journal of neurophysiology.

[2]  J. Goldberg,et al.  Physiology of peripheral neurons innervating semicircular canals of the squirrel monkey. I. Resting discharge and response to constant angular accelerations. , 1971, Journal of neurophysiology.

[3]  J. Goldberg,et al.  Physiology of peripheral neurons innervating otolith organs of the squirrel monkey. I. Response to static tilts and to long-duration centrifugal force. , 1976, Journal of neurophysiology.

[4]  Paul Van de Heyning,et al.  Vestibular function testing , 2007, Current opinion in neurology.

[5]  J. Goldberg,et al.  Physiology of peripheral neurons innervating semicircular canals of the squirrel monkey. 3. Variations among units in their discharge properties. , 1971, Journal of neurophysiology.

[6]  T. Jones,et al.  Short latency compound action potentials from mammalian gravity receptor organs , 1999, Hearing Research.

[7]  D. Pappas,et al.  Extratympanic electrocochleography: diagnostic and predictive value. , 2000, The American journal of otology.

[8]  A. Grossmann,et al.  Cycle-octave and related transforms in seismic signal analysis , 1984 .

[9]  P. Poon,et al.  EMG Power Spectrum Patterns of Anterior Temporal and Masseter Muscles in Children and Adults , 1989, Journal of dental research.

[10]  Richard E. Gans Video‐oculography: A new diagnostic technology for vestibular patients , 2001 .

[11]  G M Halmagyi,et al.  Myogenic potentials generated by a click-evoked vestibulocollic reflex. , 1994, Journal of neurology, neurosurgery, and psychiatry.

[12]  T. Balkany Hearing and Equilibrium , 1992, Otolaryngology Head & Neck Surgery.

[13]  M Forshaw,et al.  A critical review of the role of neonatal hearing screening in the detection of congenital hearing impairment. , 1997, Health technology assessment.

[14]  G. Turin,et al.  An introduction to matched filters , 1960, IRE Trans. Inf. Theory.

[15]  J. Goldberg,et al.  Physiology of peripheral neurons innervating otolith organs of the squirrel monkey. II. Directional selectivity and force-response relations. , 1976, Journal of neurophysiology.

[16]  J. Goldberg,et al.  Physiology of peripheral neurons innervating otolith organs of the squirrel monkey. III. Response dynamics. , 1976, Journal of neurophysiology.

[17]  Kerry Hourigan,et al.  Computer models of the vestibular head tilt response, and their relationship to evestg and meniere's disease , 2010 .

[18]  Christopher A Shera,et al.  Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves. , 2003, The Journal of the Acoustical Society of America.

[19]  J. Kormylo,et al.  Two-pass recursive digital filter with zero phase shift , 1974 .

[20]  J. Daube,et al.  Muscles Alive , 1981, Neurology.

[21]  C. Iseli,et al.  A comparison of three methods of using transtympanic electrocochleography for the diagnosis of Meniere's disease: Click summating potential measurements, tone burst summating potential amplitude measurements, and biasing of the summating potential using a low frequency tone , 2010, Acta oto-laryngologica.

[22]  J. Goldberg,et al.  Efferent-Mediated Fluctuations in Vestibular Nerve Discharge: A Novel, Positive-Feedback Mechanism of Efferent Control , 2006, Journal of the Association for Research in Otolaryngology.

[23]  S. Charpier,et al.  Synchronous bursting in a subset of interneurons inhibitory to the goldfish Mauthner cell: synaptic mediation and plasticity. , 1994, Journal of neurophysiology.