The effect of massed practice and somatosensory stimulation on upper extremity function and cortical plasticity in individuals with incomplete cervical spinal cord injury
Date of Award
Doctor of Philosophy (Ph.D.)
First Committee Member
Edelle Field-Fote, Committee Chair
The effects of massed practice (MP) and somatosensory stimulation (SS) on upper extremity function and neural plasticity have not been studied in individuals with chronic incomplete spinal cord injury (SCI). We have investigated whether functional, cortical, spinal and muscle changes can be induced in response to these interventions in individuals with incomplete cervical SCI. The specific questions addressed in these studies were: (1) Is there a specific intensity of SS that promotes the greatest increase in pinch grip strength and cortical excitation in non-disabled individuals? (2) Does the combination of MP and SS (MP+SS) produce greater increases in upper extremity function (UE), pinch strength, and cortical excitation than does MP alone in individuals with incomplete cervical SCI? (3) What is the effect of MP+SS, MP, or SS on sensory function, UE function, pinch grip force, and cortical, spinal and neuromuscular excitability in individuals with incomplete cervical SCI?Chapter II examines the effect of three different intensities of SS on pinch grip force and cortical excitation in non-disabled subjects. Cortical excitability and pinch grip force increase significantly after stimulation at motor threshold intensity, whereas stimulation at sensory threshold or 2x motor threshold intensity decrease cortical excitation and do not affect pinch grip strength.Chapter III compares the effect of MP+SS on UE function, pinch grip force, and cortical plasticity to the effect of MP in individuals with incomplete SCI. UE function and pinch grip force improve with MP+SS, while cortical excitability does not change in either group.Chapter IV examines the effect of MP+SS, MP or SS on UE function, pinch grip force, and excitability at the level of the cortex, spinal cord and muscle in individuals with incomplete SCI. MP+SS or SS are associated with significant improvements in UE function, pinch grip force and sensory function, SS increases spinal excitability, and MP+SS produces a trend for increased cortical excitability.In summary, our results provide evidence that MP+SS has a functional benefit in individuals with incomplete cervical SCI. Application of SS to induce functional changes may have benefit in situations where individuals are too weak or unable to participate in intensive rehabilitation. Further studies on the duration of these protocols should be performed to determine the long-term effect of such training on function and neuromuscular plasticity.
Health Sciences, Rehabilitation and Therapy
Beekhuizen, Kristina Smith, "The effect of massed practice and somatosensory stimulation on upper extremity function and cortical plasticity in individuals with incomplete cervical spinal cord injury" (2004). Dissertations from ProQuest. 2154.