Models of Tinnitus Flashcards
What is the limbic system?
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
What is the autonomic nervous system?
Controls vital bodily functions such as homeostasis which is maintenance of bodily stability
Activated when we hear potentially dangerous sounds
What is the efferent auditory system?
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
What are the efferent fibers that descend from the olivary complex in the brainstem?
Olivocochlear bundle (OCB)
Medial OCB fibers lead directly to the outer hair cells
Lateral OCB fibers have indirect connections with inner hair cells
Where is tinnitus generated?
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)
What are tinnitus models?
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
What are the different models of tinnitus?
Many different models
Neurophysiological models and psychological/cognitive models
What is the neurophysiological model of tinnitus?
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)
What are the 3 main proposed mechanisms for how tinnitus is coded in the auditory cortex? (neurophysiological models)
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)
Is tinnitus thought to possibly be the result of maladaptive plasticity in the central nervous system? (neurophysiological models)
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
What is the process from hearing loss to tinnitus? (neurophysiological)
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
What is central gain? (neurophysiological)
Refers to a compensatory increase in the central auditory activity in response to the loss of sensory input
Related to loss of hearing
What is jastreboff’s neurophysiological model?
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)
What are the key systems for jastreboff’s model?
Limbic System
Sympathetic Autonomic Nervous System (fight or flight)
Reticular Formation (awareness)
Does jastreboff classify tinnitus as peripheral or central?
He doesn’t think it should be categorized
All levels are involved in each case to varying degrees, and all parts are essential
Does jastreboff suggest that tinnitus becomes problematic when negative associations are formed with the tinnitus perception? (tiger in the room)
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
What are the limitations of the neurological models?
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
Do the characteristics of tinnitus directly influence its psychological impact on patients?
No
It could affect patients even if its really soft
It could not bother someone when its really loud
What are symptoms most commonly associated with tinnitus?
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)
What is the vicious cycle of tinnitus?
Tinnitus can trigger anxiety, which reinforces tinnitus perception, creating a feedback loop, leading to increased arousal and emotional distress
Can stress and emotional states contribute to tinnitus development and severity?
Yes
Can insomnia worsen the functional and emotional toll of tinnitus symptoms?
Yes
Does quality of life (due to tinnitus) affect the individual as well as their family?
Yes
Management of tinnitus improves quality of life for the whole family
What is tinnitus perception vs reactions?
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
Have several psychological models been proposed to explain why chronic tinnitus become distressing?
Yes
What is Hallam’s model? (psychological)
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
What is hallam’s habituation theory?
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
What is some evidence for hallam’s habituation theory?
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
What are some factors that can prevent the habituation of tinnitus (hallam)?
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)
What can reactivate awareness of previously ignored tinnitus?
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
What are some treatment strategies that focus on maintaining low arousal (to facilitate habituation)?
Relaxation therapy (to lower autonomic arousal and interrupt loop)
Formal cognitive therapy (alters emotional response to tinnitus, reduces perceived distress and aids habituation)
Who proposed the cognitive behavioral models of tinnitus?
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)
What is the cognitive behavioral model of tinnitus?
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
Why is the cognitive behavioral model different from other models?
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)
What are some implications for tinnitus management? (cognitive behavioral)
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
