Brain Physiology in Polio Survivors
Condition: Postpoliomyelitis
MeSH terms: Poliomyelitis
Study type: Observational

Summary: 
      OBJECTIVE: Many persons who survive poliomyelitis develop pain, weakness, and fatigue many
      decades later. It is not known why some persons develop this syndrome and others do not. One
      possibility is that polio caused subclinical damage to the motor cortex. Autopsies in some
      polio patients have found damage to the brainstem and motor cortex as well as to spinal motor
      neurons. Alternatively, polio may have spared the motor cortex, but the cortex reorganized in
      different ways to compensate for the loss of spinal motor neurons. This study will first
      assess the integrity of central motor pathways in polio survivors with and without postpolio
      syndrome. The second goal will be to investigate differences in the intracortical mechanisms
      for controlling muscles affected and unaffected by polio.

      STUDY POPULATION: 60 patients who survived polio in childhood. Only patients with an
      unequivocal history of polio will be referred to this study. Half of the patients will have
      the post-polio syndrome. 30 normal volunteers, aged 21-75.

      DESIGN: Patients will be screened at the collaborating institution, the Uniformed Services
      University of the Health Sciences, which will also perform sensory evoked potential testing
      and MRI. At NIH, motor evoked potentials will be elicited from all four limbs using
      transcranial magnetic stimulation to assess central motor conduction time and threshold.
      Intracortical facilitation will be used to assess using paired-pulse magnetic stimulation.
      Two muscles will be tested in each patient, one affected by polio and one unaffected by
      polio. In the affected muscle, intracortical facilitation will be assessed again after
      exercises it until it fatigues.

      OUTCOME PARAMETERS: Cortical thresholds and central motor conduction times to all four limbs
      will be measured in patients and compared to normal subjects. The mean intracortical
      facilitation at rest will be compared in affected and unaffected muscles in polio patients
      with and without post-polio syndrome.
    

Detailed description: 
      OBJECTIVE: Many persons who survive poliomyelitis develop pain, weakness, and fatigue many
      decades later. It is not known why some persons develop this syndrome and others do not. One
      possibility is that polio caused subclinical damage to the motor cortex. Autopsies in some
      polio patients have found damage to the brainstem and motor cortex as well as to spinal motor
      neurons. Alternatively, polio may have spared the motor cortex, but the cortex reorganized in
      different ways to compensate for the loss of spinal motor neurons. This study will first
      assess the integrity of central motor pathways in polio survivors with and without postpolio
      syndrome. The second goal will be to investigate differences in the intracortical mechanisms
      for controlling muscles affected and unaffected by polio.

      STUDY POPULATION: 60 patients who survived polio in childhood. Only patients with an
      unequivocal history of polio will be referred to this study. Half of the patients will have
      the post-polio syndrome. 30 normal volunteers, aged 21-80.

      DESIGN: Patients will be screened at the collaborating institution, the Uniformed Services
      University of the Health Sciences, which will also perform sensory evoked potential testing.
      At NIH, motor evoked potentials will be elicited from all four limbs using transcranial
      magnetic stimulation to assess central motor conduction time and threshold. MRI scans of the
      brain or spine will be performed in patients with abnormal evoked potentials. Intracortical
      facilitation will be assessed using paired-pulse magnetic stimulation. Two muscles will be
      tested in each patient, one affected by polio and one unaffected by polio. In the affected
      muscle, intracortical facilitation will be assessed again after exercises it until it
      fatigues.

      OUTCOME PARAMETERS: Cortical thresholds and central motor conduction times to all four limbs
      will be measured in patients and compared to normal subjects. The mean intracortical
      facilitation at rest will be compared in affected and unaffected muscles in polio patients
      with and without post-polio syndrome.
    

Keywords: Post Polio Syndrome; Magnetic Stimulation; Fatigue; Exercise; Weakness; Transcranial Magnetic Stimulation; Post-Exercise Fatigue; Motor Neuron Disease; Cortical Reorganization; Intracortical Facilitation; Polio; Healthy Volunteer; HV