Muscle Tension Dysphonia
This is the most common diagnosis in Voice Clinics, with up to 40% of patients diagnosed with this [1].
What are the symptoms?
These can be any or several of the following:
What is causing these symptoms?
Muscle Tension Dysphonia (MTD) is an imbalance in muscle use in and around the larynx. This builds up as muscular tension, and leads to an inefficient system that may feel like a struggle.
In Primary MTD, the cause can be:
In Secondary MTD the underlying cause is a vocal pathology, the MTD is the result of trying to work around this. It is a compensatory adjustment.
The only way to reliably tell the difference between Primary and Secondary MTD is to have a nasendoscopic assessment in a voice clinic. If there is no visible pathology of the vocal folds, then the muscle tension is functional.
What is a functional disorder?
Functional voice disorders are changes to the voice without an obvious anatomical or physiological cause. Instead, they are the result of an uncoordinated voice system. The muscles in and around the larynx are either over-working or under-working. The ones that are over-working will be causing strain and fatigue.
Why does stress or anxiety contribute to these physical changes?
When we are anxious, our autonomic nervous system is spending more time in the Sympathetic state. This is our ‘fight or flight’ response, alerting our body to danger and preparing it for action. Our muscles are primed for a response, and are held to some extent. If we are slightly anxious, in a continual state of low-level worry, then our muscles will be slightly held for more of the time. As they are holding, their function is less efficient. This builds over time in systems that are either sensitive to emotional change, or systems that we are using a lot. If you are a professional voice user, it’s your voice that will show the signs of strain
What happens next?
If you are troubled by your voice symptoms, book an appointment with your doctor to get a referral to a voice clinic. If you are diagnosed with MTD you will probably be offered speech therapy. This will help you to relearn the habits and patterns of use that have contributed to the problem. If you are waiting for an appointment, therapy is useful in the meantime to help you to manage your vocal habits.
If you are a professional voice user, you may want to work with a Singing Voice Rehabilitation Specialist alongside your speech therapy.
Manual therapy such as gentle vocal massage can be useful to reset your vocal system and relieve some of the symptoms.
If you suspect that anxiety is part of the cause, you may find that counselling or psychotherapy is a helpful path for you.
Some more information on the pathology of MTD
British Voice Association website
Some more information on the complexity of the causes, and the subtle build-up over time
In all physical activity, efficient use is essential for injury prevention [2]. In singing, a decrease in efficiency will be linked to a compromised level of healthiness, whether the person concerned perceives this. If taken further, a decrease in efficiency will incrementally increase the stress on the tissues that could eventually lead to a collapse of the system. Physical stress theory [3] states that a physical activity should function within the maintenance stress range of the individual, this depends on prior strength and training. An increase in levels of stress to the tissues, depending on the magnitude, time, and direction of movement, will ultimately cause the system to reach the maximum stress threshold. This process, although requiring a gradual change over time, will go unnoticed until the cumulative effect of this vocal behaviour passes the threshold of tolerance [4]. As the maximum stress threshold is reached, the ability of the system to perform the function will exhibit an acute response, the system will collapse with either a drastically reduced ability to function, or in some cases, acute pain. This appears to be a single event, and the singer will seek to identify it as such. It is, however, the result of a longer-term cumulative build-up of stress to the system.
The same tipping point happens with anxiety and arousal. There is a crucial point in everyone beyond which the outcome can be disastrous. If physiological arousal (a measure of the heart rate of the individual) and cognitive anxiety (the degree of anxiety relating to performance expectation of the individual) increase to a critical level, then performance levels will rapidly deteriorate [5]. Catastrophe theory [6] suggests that once this critical level of cognitive anxiety is exceeded, it is not possible to regain performance levels with small adjustments to the predictor variables, physiological arousal, and cognitive anxiety. This is illustrated by a sudden dip and further collapse of the performance level as the cognitive anxiety increases. If cognitive anxiety is kept to a low level, then physiological arousal and performance level can have a positive correlation.