Saltzmann and Ersner (1947) - hearing aids amplified background noise, mask tinnitus
If hearing loss try HA, less interference with speech, no noise to produce damage, improve speech understanding
Commercial tinnitus maskers with or without HA
Complete or partial mask
No clear guidelines for use
Hearing Aides and Maskers
Narrowband noise (less 1/2 octave) tonal character, more annoying
Conservative approach - lowest level with adequate relief, need not be worn continuously
No protocol which ear, unilateral, bilateral
Electrical Stimulation
DC (direct current) to round window or promontory could reduce tinnitus
DC may produce permanent damage, cannot be used clinically
AC (alternatig current)
External stim to tympanic membrane, transtympanically on promontory, tanscutaneously in pre and post auricular region
Electrical Stimulation
Ext. AC stim. results mixed, some promising
One commercial extracochlear wearable device marketed 1985
1986 Dobie 1 in 20 benefited
Intracochlear Electrical Stimulation
Observations that cochlear-implant patients reduction in tinnitus while listening to speech
Few received CI explicitly for tinnitus
1984 House 5 patients severe to profound HL, CI placed for tinnitus relief, no stim. only one reported benefit listening to speech.
Intracochlear Electrical Stimulation
1989 Hazell - six totally deaf, CI implant and trials with sinusoidal stim.
Able to reduce tinnitus in all 6 with 100 Hz sinusoid
Two forego speech processor and used just for tinnitus relief
One turn on current, turn off tinnitus “like a light switch”
Surgery
Effective in treating conditions, tinnitus is symptom eg. otosclerosis, acoustic neuroma, glomus jugulare
Lituratue discusses cochlear neurectomy and microvascular decompression of the cochlear nerve
Results not consistent
Few otologists advocate use of surgery
Validates hypothesis tinnitus gen. central
Neurophysiological Approach to Tinnitus and Habituation
New theory
Previous theories share belief that process producing tinnitus restricted to auditory pathway and cochlea
Models focused on tinnitus generation, treated auditory pathway as passive, unchangeable transmitters of signal to auditory cortex
Neurophysiological Model
Diagnostic efforts concentrated on psychoacoustical description (loudness, pitch, maskability)
These no help in predicting treatment outcome, no explaination why same descript produced drastic different annoyance
This model postulates - tinnitus results from multiple interactions of a number of subsystems in nervous system
Neurophysiological Model
Auditory pathway role in development and appearance of tinnitus as sound perception
Other systems, limbic system, tinnitus annoyance
Problem - perception becomes associated with neg. emotions, fear , and threat
Limbic system activates autonomic nervous system resulting in annoyance
Neurophysiologic Model
Because annoyance primarily dependent on limbic system which is a perception by the individual and an associated emotional state, psychoacoustical characterization of tinnitus irrelevant
Habituation
Def. - The disappearance of reactions to sensory stimulus because of repetitive exposition of a subject to this stimulus and the lack of positive or negative reinforcement associated with this stimulus
Brain ordering of tasks 1) importance of signal esp. if danger 2) novelty
If signal not assoc. with event or indicate danger, not new, undergoes habituation, and after repetition in not perceived
Habituation
Accomplished by directive counseling - educate patient of potential mechanisms of tinnitus, discuss results of all audiologic and medical tests and relavance
Once patient understands, level of annoyance decreases
Repetative visits reinforce and eliminate negative association evoked by tinnitus
Habituation
Directive counseling essential but not sufficient to achieve permanent habituation
Need to enhance auditory background ie. partial masking, particularly in quiet envir.
Increased background spontaneous and evoked activity in auditory pathways, reduces contrast of tinnitus to background noise facilitating habituation
Must avoid masking tinnitus completely
Habituation
By def. once signal is masked it cannot be habituated to
Reconditioning of connections in subcortical centers cannot occur if stimulus (tinnitus) is absent
Tinnitus masking 15 yrs no changes in tinnitus, evidence of habituation, decreased annoyance
One year habituation therapy - aware only small percent of time, annoyance decreased
Habituation - Technique
Fitted binaurally with broad-band noise generator
Use for at least 6 hrs per day, part. in quiet
If HL, HA are also used
Process requires 12 months
Jastreboff insists 6 more months to ensure plastic changes in brain establised
After that time noise generators discontinued
Habituation - Results
Jabstreboff reports 83% of patients exhibit significant improvement with combined therapy
Summary
Important to differentiate types of tinnitus
Must recognize when tinnitus part of symptomatology of underlying disease verses merely auditory annoyance
Patience and understanding of patient’s experience important
Paraauditory tinnitus treatable by standard medical/surgical therapy
