Brain Plasticity and Speech Pathology

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Neural (or brain) plasticity is the ability of the brain to change or adapt. This occurs in response to the environment, experience, behaviour, disease or injury. We can learn due to the fact that our brains are malleable, or “plastic”. There is much research still to be done on this topic. However, scientists have used studies of humans and animals to develop a set of principles of neural plasticity. In the clinic, these principles help us understand the best ways to encourage communication skills in the case where a child’s development is delayed or disordered, when they are learning to change “incorrect” speech patterns (eg. a lisp or stuttering), or after a brain injury. In our homes, these principles help us understand how best to encourage communication and other skills in our children.

1. Use It or Lose It

Brains that are not engaged in tasks for an extended period of time begin to degrade. This principle means that it is important to encourage our parents who are elderly, to continue to engage in communication with others. Involving them in family life, where possible, helps them to maintain communication and thinking skills.

2. Use It and Improve It

raining can lead to changes in the structure and function of brain mechanisms involved in behaviours such as communication. This is why speech and language therapy can help people of all ages and ability levels to improve communication skills.

3. Training Needs to be Specific

Training may lead only to change in the specific skill being trained. This is why there has been a movement away from training people in non-speech skills (eg. blowing air and moving the tongue without speaking) in the hope that this will improve speech skills. As much as possible, Speech Pathologists focus on training a person in the actual skills that they need for everyday communication.

4. Repetition Matters

Simply engaging the brain in a training activity during speech therapy is not enough: repetition is required to bring lasting improvements. “Practice makes perfect”. This is why skills are often practised repetitively during speech therapy. Doing speech therapy homework is so important as it allows additional practice of tasks. I often find that how quickly a person responds to therapy is directly related to the amount of practice done in the clinic (frequency of appointments and amount of practice achieved within appointments) and at home (ie. frequency of homework).

5.Intensity of Practice Matters

Training should be continuous over long periods to encourage positive changes to the brain. Therapy usually needs to be intensive, especially in the case of motor speech disorders such as apraxia. Clients are encouraged to get in as many repetitions as possible, in order to promote change most quickly. Also, this principle supports regular therapy appointments rather than sporadic or spread-out appointments.

6. When to Start Treatment

There are optimal “windows” of opportunity for improvement. For example, we know that the preschool years are the prime time for stuttering therapy. Early intervention is ideal in the case of a developmental speech or language disorder. A lot of research points to the effectiveness of therapy initiated as soon as possible after a brain injury. Rehabilitative voice therapy usually should be initiated soon after laryngeal surgery or illness, after a short period of vocal rest.

7. Therapy Must Be Relevant and Meaningful

Training that is purposeful and related to the behaviour being trained will promote positive changes to the brain. Meaningful tasks enhance motivation and attention to task. Therapy tasks should be meaningful to the person, and the person should be involved in goal-setting to ensure that goals are relevant and meaningful to them.

8. Age Matters

The brain can change and adapt at all ages, but it is more adaptable in younger compared to older people. There are differences in the brain structures and functions of an old and young brain, reflecting the changes in thinking that occur with ageing. A few different factors may influence brain changes due to ageing, including life experiences, and the amount of physical and mental activity engaged in regularly. It is brain plasticity that enables an ageing person to compensate for reducing thinking skills.

9. Transference Can Occur

Sometimes training in one skill can lead to improvements in related, untrained skills. This principle appears to contradict the principle of specificity (see #3 above). However, one study showed that “loud speech” therapy improved swallowing in a group of people with Parkinson’s Disease. Similarly, expiratory muscle strength training is reported to improve airway protection in people with neuromuscular disease, despite this not being directly trained. Much more research is needed, in order to understand whether these therapies were responsible for the enhancement of other behaviours or whether transference occurred regardless of the type of therapy.

10. Interference Can Occur

Plasticity can allow brain changes which interfere with skills. The research around this principle has focused on the use of limbs after brain injury and there is little known about how this principle may relate to Speech Pathology. However it makes sense that enhancing some speech or voice skills may interfere with other communication skills – eg. some stuttering and articulation therapies affect the rhythm of speech.

Some Implications…

#1: Speech therapy can improve communication skills.

#2: Speech therapy needs to address specific communication skills.

#3: High-intensity, repetitious therapy is most likely to improve communication skills.

#4: Therapy needs to be appropriately-timed – early intervention for children with developmental speech and language disorders and stuttering, people with voice disorders and people post-stroke.

#5: People engaging in therapy should be involved in goal-setting. They should understand and support their goals.

#6: As we age, we need to work to MAINTAIN our communication skills. Elderly people need to engage in communication regularly.

References

Translating Principles of Neural Plasticity Research on Speech Motor Control Recovery and Rehabilitation (2008), Ludlow, C.L., Hoit, J., Kent, R., Ramig, L. O., Shrivastav, R., Strand, E., Yorkston, K., Sapienza, C. Journal of Speech Language and Hearing Research, 51(1):S240-58

Principles of Experience-Dependent Neural Plasticity: Implications for Rehabilitation After Brain Damage (2008), Kleim, J.A. & Jones, T.A., Journal of Speech, Language, and Hearing Research, Vol. 51, S225–S239

 

DISCLAIMER: This advice is not intended to replace the recommendations of a Speech Pathologist for an individual with a communication impairment. If you have concerns about your child’s speech and language development, please contact a Speech Pathologist.

 

 

 

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