Models of Tinnitus

Question 1

What is the limbic system?

Answer 1

Serves the functions of emotion, long-term memory, and other aspects of behavior
One limbic system structure called the amygdala is important in a person’s emotional response to sounds

Question 2

What is the autonomic nervous system?

Answer 2

Controls vital bodily functions such as homeostasis which is maintenance of bodily stability
Activated when we hear potentially dangerous sounds

Question 3

What is the efferent auditory system?

Answer 3

Descending pathways
Begins at the auditory cortex and includes pathways within each of the major auditory centers for the afferent auditory system
May help improve detection, localization, and perception of speech in a setting of background noise
Function of the efferent system may be related to auditory disorders like tinnitus

Question 4

What are the efferent fibers that descend from the olivary complex in the brainstem?

Answer 4

Olivocochlear bundle (OCB)
Medial OCB fibers lead directly to the outer hair cells
Lateral OCB fibers have indirect connections with inner hair cells

Question 5

Where is tinnitus generated?

Answer 5

Anywhere on the pathway of sound
Can be multiple sites of generation in the same patient
The central auditory pathways is most likely heavily involved (sectioning the auditory nerve is often ineffective in reducing tinnitus)

Question 6

What are tinnitus models?

Answer 6

Conceptual frameworks that aim to explain the overall phenomenon of tinnitus (including its generation, perception, and associated distress)
Offer explanations for various tinnitus-related phenomena
Integrate findings from multiple research domains
Guide research and clinical approaches

Question 7

What are the different models of tinnitus?

Answer 7

Many different models
Neurophysiological models and psychological/cognitive models

Question 8

What is the neurophysiological model of tinnitus?

Answer 8

Biological basis of tinnitus
Various neurophysiological models have been proposed to explain tinnitus mechanisms, focusing on different anatomical or physiological aspects; but none have been definitively proven
There is a consensus that tinnitus results from the perception of abnormal activity (where it is happening differs)

Question 9

What are the 3 main proposed mechanisms for how tinnitus is coded in the auditory cortex? (neurophysiological models)

Answer 9

Increased spontaneous activity fed by increase or decrease in activity
Cross-fiber correlation with normal or increased spontaneous activity
More fibers with similar best frequency following hearing loss–induced auditory plasticity (brain is rewiring itself, could result in an enhancement in these sounds that the brain perceives as tinnitus)

Question 10

Is tinnitus thought to possibly be the result of maladaptive plasticity in the central nervous system? (neurophysiological models)

Answer 10

Yes
Happens in response to hearing loss or unknown causes
Lack of auditory stimulus will result in something that will produce tinnitus (system trying to compensate)
Neurophysiological models have logically nominated the increase in spontaneous activity as a mechanism of tinnitus

Question 11

What is the process from hearing loss to tinnitus? (neurophysiological)

Answer 11

Hearing loss leads to a decrease in input to the auditory system
Brain attempts to maintain homeostasis by compensating for reduced auditory input
Compensation involves increasing neural gain and sensitivity in the auditory system
Increased gain leads to higher spontaneous neural activity (even without acoustic stimulation)
Increased spontaneous activity is proposed as a key mechanism for tinnitus perception
Changes in neural activity are likely transmitted to and represented in the auditory cortex

Question 12

What is central gain? (neurophysiological)

Answer 12

Refers to a compensatory increase in the central auditory activity in response to the loss of sensory input
Related to loss of hearing

Question 13

What is jastreboff’s neurophysiological model?

Answer 13

Founder of the neurophysiological model
Foundation of TRT
Focuses on the interaction between auditory and non-auditory systems (many systems in the brain cause it)
Based on general neurophysiology and behavioral neuroscience
Overall hypothesis - many systems in the brain are involved in tinnitus, with the auditory system playing a secondary role
Peripheral auditory processes might initiate tinnitus-related activity, but auditory dysfunction is not a prerequisite for perceiving tinnitus (could happen without dysfunction in the auditory system)

Question 14

What are the key systems for jastreboff’s model?

Answer 14

Limbic System
Sympathetic Autonomic Nervous System (fight or flight)
Reticular Formation (awareness)

Question 15

Does jastreboff classify tinnitus as peripheral or central?

Answer 15

He doesn’t think it should be categorized
All levels are involved in each case to varying degrees, and all parts are essential

Question 16

Does jastreboff suggest that tinnitus becomes problematic when negative associations are formed with the tinnitus perception? (tiger in the room)

Answer 16

Yes
Focusing on tinnitus increases arousal (stress, anxiety); this makes it harder to ignore the tinnitus
The limbic system therefore must be involved in tinnitus patients who have emotional reactions (also association cortices and prefrontal cortex)
Model for TRT
Not just a sensory experience, but also has emotional and cognitive components

Question 17

What are the limitations of the neurological models?

Answer 17

Multiple possible mechanisms for tinnitus generation (occurring at all levels)
Does not explain why not everyone with hearing loss gets tinnitus
Cannot explain observations of patient in whom alleviation occurred after cutting the auditory nerve

Question 18

Do the characteristics of tinnitus directly influence its psychological impact on patients?

Answer 18

No
It could affect patients even if its really soft
It could not bother someone when its really loud

Question 19

What are symptoms most commonly associated with tinnitus?

Answer 19

Insomnia
Loss of concentration
Low mood and irritability
Anxiety
Clinical depression (likely bidirectional tinnitus can exacerbate depression and depression can make tinnitus more challenging to manage)

Question 20

What is the vicious cycle of tinnitus?

Answer 20

Tinnitus can trigger anxiety, which reinforces tinnitus perception, creating a feedback loop, leading to increased arousal and emotional distress

Question 21

Can stress and emotional states contribute to tinnitus development and severity?

Answer 21

Yes

Question 22

Can insomnia worsen the functional and emotional toll of tinnitus symptoms?

Answer 22

Yes

Question 23

Does quality of life (due to tinnitus) affect the individual as well as their family?

Answer 23

Yes
Management of tinnitus improves quality of life for the whole family

Question 24

What is tinnitus perception vs reactions?

Answer 24

Perceptions - the characteristics of the tinnitus sound itself
Reactions - refers to the impact of tinnitus on an individuals life
This has become known as the psychological model of tinnitus

Question 25

Have several psychological models been proposed to explain why chronic tinnitus become distressing?

Answer 25

Yes

Question 26

What is Hallam's model? (psychological)

Answer 26

Tinnitus might occur without auditory dysfunction, potentially triggered by psychological factors Influenced by the CNS's ability to selectively inhibit unnecessary sensory input Disruptions in this selective inhibition (particularly during high arousal states) can make tinnitus more prominent

Question 27

What is hallam's habituation theory?

Answer 27

Many individuals with tinnitus experience habituation over time (brain treats the constant presence of tinnitus as a non-threatening stimulus), leading to a gradual decrease in both awareness and distress Bothersome tinnitus is failure to habituate

Question 28

What is some evidence for hallam's habituation theory?

Answer 28

The majority of people who have tinnitus don't complain Distress from tinnitus tends to decrease over time No relationship between tinnitus loudness and distress levels (individual psychological adaptation) Individuals often grow more tolerant of tinnitus, even if it doesn't go away

Question 29

What are some factors that can prevent the habituation of tinnitus (hallam)?

Answer 29

High levels of arousal (stress or anxiety can increase awareness of tinnitus) Sudden onset (makes it more difficult for the brain to adapt) Intense of unpredictable tinnitus (harder to adapt) Emotional significance (if associated with strong negative emotions, it can become more difficult to habituate) Neural pathway damage (damage in the pathways involved in habituations can interfere with the normal habituation process) Dishabituation (shifts in a person's mental state that can lead to re-awareness)

Question 30

What can reactivate awareness of previously ignored tinnitus?

Answer 30

Stress or psychological changes An orienting response to tinnitus could interrupt normal behavior, leading to increased arousal and decreased habituation This would produce a pathophysiological positive feedback loop, resulting in persistence of the symptom

Question 31

What are some treatment strategies that focus on maintaining low arousal (to facilitate habituation)?

Answer 31

Relaxation therapy (to lower autonomic arousal and interrupt loop) Formal cognitive therapy (alters emotional response to tinnitus, reduces perceived distress and aids habituation)

Question 32

Who proposed the cognitive behavioral models of tinnitus?

Answer 32

McKenna (2014) This model emphasizes that tinnitus distress often stems more from an individual's reactions and perceptions of the sound rather than the auditory signal itself Foundation of CBT interventions for tinnitus patients (aims to break the cycle of distress)

Question 33

What is the cognitive behavioral model of tinnitus?

Answer 33

Negative interpretations of tinnitus increase physiological arousal and selective attention Leads to greater awareness of tinnitus (which can cause anxiety and low mood) Person notices the tinnitus more This creates a cycle, reinforcing the negative interpretation Safety seeking behaviors (avoidance) may provide short-term relief (prevents long-term adaptation) Selective attention can distort how tinnitus is perceived

Question 34

Why is the cognitive behavioral model different from other models?

Answer 34

Greater emphasis on vigilance and orientation to tinnitus rather than failure to habituate Emphasizes the impact of negative thoughts and cognitive distortions on tinnitus distress (while the habituation model focuses on the brains natural ability to tune out the sound over time)

Question 35

What are some implications for tinnitus management? (cognitive behavioral)

Answer 35

Targets reaction to the tinnitus Correcting negative automatic thoughts Reducing sympathetic autonomic nervous system activity Reducing selective attention and monitoring for tinnitus-related cues Correcting distorted perceptions of tinnitus intensity and its impact on functioning Correcting counterproductive safety behaviors Correcting inaccurate beliefs