Residual pelvic floor muscle activation following SCI

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Lay summary by Alison Babichuk

Edited by Rona Herzog, Crystal Han

This is a lay summary of the original article by ICORD researchers Dr. Tania Lam, Dr. Mark Carpenter, and their colleagues Alison Williams, Gevorg Eginyan, Emily Deegan, and Mason Chow. Read the original article here.

Pelvic floor muscles are crucial for everyday living, as they are involved activities such as coughing, postural adjustments, and controlling our bladders.  In those diagnosed with a motor-complete spinal cord injury (mcSCI), movement is thought to be lost below the level of the injury, which would impact the function of the pelvic floor muscles. However, previous studies in people with mcSCI have shown that they are able to voluntarily control abdominal and leg muscles to below their injury level to some extent, and stimulation of certain brain regions using a method called transcranial magnetic stimulation (TMS) can result in slight motor activity in the trunk and leg muscles. These previous findings indicate the presence of some motor function in the lower limb regions after an mcSCI. However, this study was the first to examine if people with mcSCI also have motor activity in their pelvic floor muscles.

What was the purpose of the study?

This study set out to determine if there was remaining innervation to the muscles in those with mcSCI. The researchers focused on investigating if the pelvic floor muscles were able to be activated on their own, in addition to being co-activated along with other muscles. Finally, researchers also investigated if pelvic floor muscles showed motor activity in response to TMS over certain brain regions of participants.

How was the study done?

Participants all had mSCI, and were between the ages of 19-60. To see if the participants could voluntarily activate their pelvic floor muscles, they performed various physical tasks which included:

  • abdominal exercises,
  • hip extensions,
  • pelvic floor exercises- known as “Kegel Exercises”

To see if the participants retained a neural connection from their brain to their pelvic floor, the researchers applied TMS over the brain and examined with special sensors if the pelvic floor responded to this type of stimulation

What were the results?

The researchers found that abdominal exercises, like sit-ups, elicited significant motor activity in the pelvic floor muscles of the participants.

All participants were found to have decreased levels of pelvic floor muscle activation in comparison to control participants. All participants showed some degree of pelvic floor muscle activation in response to TMS.

Why is this important?

Pelvic floor muscles play a key role in bladder control, which is ie one reason why people with mcSCI with weakened pelvic floors often experience urinary dysfunctions. It is therefore important to investigate interventions for people with mcSCI which target the pelvic floor muscles.

Researchers found that activation of pelvic floor muscles is possible following an mcSCI, but only through co-simultaneous activation of other muscles, namely in the trunk muscles. Researchers were also able to demonstrate there is some retention of the connections to the pelvic floor muscles from the brain in the participants, which was seen through the motor activation during TMS.

These findings are important as they suggest people with mcSCI may retain some pelvic floor muscle function post injury. Future studies should continue to explore the extent to which people with mcSCI can activate their pelvic floors, and investigate if pelvic floor muscle training is a viable option to treat urinary dysfunction.