Today’s Topic is a continuation of last weeks topic of neuroplasticity. I got my latest journal of Physical Therapy and the very last article in this month’s addition was titled “Promoting Neuroplasticity for Motor Rehabilitation After Stroke: Considering the Effects of Aerobic Exercise and Genetic Variation on Brain-Derived Neurotrophic Factor”. To say the least, it was a very interesting article and here is some food for thought and how this can pertain to the goal of improving in regards to daily function when faced with life challenges of having a stroke, spinal cord injury or being faced with a diagnosis of Parkinson’s or Multiple Scelorsis.
We talked about the basic concept of neuroplasicity and strategies used to improve functional mobility and make new connections. The above article mentions brain-derived neurotrophis factor (BDNF) has emerged in the neuroplasticity research literature as a key facilitatior of neuroplasticity involved in motor learning and rehabilitation. Other research is demonstrating that BDNF increases with bouts of aerobic exercise. With these two thoughts, this article mentioned numerous other studies and the idea that using aerobic exercise as priming tool before doing rehabilitation on a specific motor task like walking, rolling in bed or picking up an object with your hand may enhance the brain’s ability to make new connections due the increased BDNF.
We know that aerobic exercise benefits us physically with improvement in general health and fitness but it also helps alter the brain positively through molecular signaling pathways. The basis of reseach is done in animal models so in one study rats showed that disrupting BDNF synthesis with medication impaired skilled motor performance and training. While on the other hand, injections of BDNF partially restored the primary motor function. Other studies specifically related to exercise demonstrated that exercise programs combining aerobic and resistance training programs at a moderate exertion rate 2 to 3 days a week for 12 weeks and 6 months improved executive function and memory in individuals with chronic stroke. Having worked with a few patients over several years that are post stroke 2-5 years have benefited from consistent aerobic and resistance training both on land in the pool. As is true in most cases, if one stops consistent aerobic exercise then the positive affects of motor learning, improved memory and cognition can decrease. The article goes on to site many other studies and brings up important genetic factors and the idea that this theory is scientifically sound and should be explored in greater depth!
The take home message is this:
1. A bout of aerobic exercise that incorporates a session > 30 minutes, intensity of 70% of max heart rate, frequency of 4 days a week and combination of aerobic and resistance exercises.
2. This exercise primes the central nervous system for neuroplasticity by increasing BDNF in cerebral cortex, spinal cord, hippocampus and cerebellum.
3. Complete motor re-training and task specific training like walking without device, sitting to stand or reaching for objects.
4. Ultimately, the theory is that using this sequence with increase the response to rehabilitation by facilitating a long lasting/increased strength of the connection between 2 neurons, a better dendrite formation in neural circuits supporting movement and learning.
When I look back at the patients who have been the most successful, there is some truth and validity to this theory. The people that put more time in, did more on the treadmill, recumbant stepper, cycle before an actual specific session of PT tended to be my more successful patients in terms of gaining their mobility and function back. My clients that I have been seeing for a few years with a chronic condition such as a stroke who participate in regular exercise 3-4 a week are still making improvements in their speech, cognition and functional mobilty 2 to 5 years post. Interesting food for thought for practitiones and individuals faced with these unexpected challenges. As always there is hope!
Mang CS, Campbell KL, et. al. Promoting Neuroplasticity for Motor Rehabilitation After Stroke: Considering the Effects of Aerobic Exercise and Genetic Variation on Brain-Derivd Neurotrophic Factor. Physical Therapy. 2013;93:1707-1716.