Relationship of acoustic stimulation and tinnitus suppression by electrical stimulation

Electrical stimulation of the auditory system results in auditory perception as well as auditory suppression. Historically, this is well documented. The recent application of advances of high technology and microsurgery of the ear have allowed basic science and clinical investigation to have access to electrical stimulation of the auditory system and its response. It is historically of great interest that such investigation in the past always involved attempts for evaluation and treatment for either auditory stimulation and/or auditory suppression. I believe the work of Aran (1981) reawakened recent interest in electrical stimulation of the auditory system for tinnitus suppression as well as auditory stimulation. Briefly, in his investigation of a deaf patient, he observed the following: (a) negative currents were more effective than positive currents for auditory stimulation; (b) positive current pulses reduced (suppressed) the intensity of tinnitus; (c) electrical stimulation in deaf patients by negative currents resulted in some sound perception. (In the congenitally deaf patients, it is difficult to evaluate the sensation produced); (d) the intensity of positive pulses necessary to suppress tinnitus is always higher than that of negative pulses resulting in auditory perception; (e) for positive pulses, the range between the threshold of tinnitus suppression and auditory perception when pulses of intermediate intensity are used, without inducing auditory perception, is wide enough to achieve total tinnitus suppression. (In other words, the current effective for electrical stimulation suppressing tinnitus is at a strength well below that producing auditory sensation); (f) negative electrical pulses can produce two different sounds-tinnitus and an auditory sensation; (g) electrical stimulation via the promontory and/or round window can be used both for auditory stimulation as well as for auditory suppression.

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Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

Journal of Neurophysiology ◽

10.1152/jn.2000.83.4.2145 ◽

2000 ◽

Vol 83 (4) ◽

pp. 2145-2162 ◽

Cited By ~ 24

Author(s):

Ralph E. Beitel ◽

Russell L. Snyder ◽

Christoph E. Schreiner ◽

Marcia W. Raggio ◽

Patricia A. Leake

Keyword(s):

Electrical Stimulation ◽

Auditory System ◽

Pulse Rate ◽

Auditory Nerve ◽

Round Window ◽

Electrode Array ◽

Scala Tympani ◽

Behavioral Thresholds ◽

Current Pulses ◽

Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

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Changes in Prefrontal Cortex–Thalamic Circuitry after Acoustic Trauma

Biomedicines ◽

10.3390/biomedicines9010077 ◽

2021 ◽

Vol 9 (1) ◽

pp. 77

Author(s):

Kristin M. Barry ◽

Donald Robertson ◽

Wilhelmina H. A. M. Mulders

Keyword(s):

Electrical Stimulation ◽

Prefrontal Cortex ◽

Auditory System ◽

Acoustic Trauma ◽

Neuron Activity ◽

Compensatory Mechanism ◽

Efferent Connections ◽

Medial Geniculate ◽

Central Auditory Pathways ◽

Stimulation Of

In the adult auditory system, loss of input resulting from peripheral deafferentation is well known to lead to plasticity in the central nervous system, manifested as reorganization of cortical maps and altered activity throughout the central auditory pathways. The auditory system also has strong afferent and efferent connections with cortico-limbic circuitry including the prefrontal cortex and the question arises whether this circuitry is also affected by loss of peripheral input. Recent studies in our laboratory showed that PFC activation can modulate activity of the auditory thalamus or medial geniculate nucleus (MGN) in normal hearing rats. In addition, we have shown in rats that cochlear trauma resulted in altered spontaneous burst firing in MGN. However, whether the PFC influence on MGN is changed after cochlear trauma is unknown. We investigated the effects of electrical stimulation of PFC on single neuron activity in the MGN in anaesthetized Wistar rats 2 weeks after acoustic trauma or sham surgery. Electrical stimulation of PFC showed a variety of effects in MGN neurons both in sham and acoustic trauma groups but inhibitory responses were significantly larger in the acoustic trauma animals. These results suggest an alteration in functional connectivity between PFC and MGN after cochlear trauma. This change may be a compensatory mechanism increasing sensory gating after the development of altered spontaneous activity in MGN, to prevent altered activity reaching the cortex and conscious perception.

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C-Fos immunoreactivity mapping of the auditory system after electrical stimulation of the cochlear nerve in rats

Hearing Research ◽

10.1016/s0378-5955(03)00236-3 ◽

2003 ◽

Vol 184 (1-2) ◽

pp. 75-81 ◽

Cited By ~ 11

Author(s):

Makoto Nakamura ◽

Steffen K. Rosahl ◽

Eyad Alkahlout ◽

Alireza Gharabaghi ◽

Gerhard F. Walter ◽

...

Keyword(s):

Electrical Stimulation ◽

Auditory System ◽

Cochlear Nerve ◽

Stimulation Of

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Electrical Stimulation of the Ear: Clinical Applications

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948309200617 ◽

1983 ◽

Vol 92 (6) ◽

pp. 621-622 ◽

Cited By ~ 14

Author(s):

M. Portmann ◽

J.-M. Aran ◽

M. Nègrevergne ◽

Y. Cazals

Keyword(s):

Electrical Stimulation ◽

Round Window ◽

Clinical Applications ◽

Positive Currents ◽

Stimulation Of

Electrical stimulation of the ear in humans was performed with an extracochlear electrode on the round window. With positive currents, suppression of tinnitus could be induced. With negative currents, auditory sensations were evoked. Since electrical stimulation with DC currents may be hazardous in the long term, it cannot yet be proposed for the suppression of tinnitus. However, electrically evoked hearing sensations with AC currents seem to be of definite interest for some totally deaf patients.

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