Does the Administration of Acute Intermittent Hypoxia in Persons With Chronic Spinal Cord Injury Make Spasticity Worse?

In the case of incomplete traumatic spinal cord injury, it is know now that muscular strength improves quickly after AIH administration, and this Increase in voluntary strength lasts from three to six hours. The Increase in strength, coupled with demonstrated improvements in spinal cord neural plasticity, makes AIH administration a potentially valuable new therapeutic intervention. AIH initially acts by releasing serotonin in the central nervous system, enhancing persistent sodium uptake (via the motor neuron soma) and activating voltage-gated calcium channels in motor neuron dendrites. There are also other effects of serotonin on motor neuron excitable channels. One potential complication of hypoxia is linked to the changes in motor neuron excitability in humans with SCI.

These issues may be relevant to our potential work on the Therapeutic efficacy of AIH in persons with incomplete spinal cord injury. In other words, if individuals are highly spastic, it may indicate that their neuronal receptor sites are inaccessible, and increasing spinal cord serotonin levels may not be beneficial.