Immediate Effects of rTMS on Excitability of the Quadriceps With Knee Osteoarthritis

The investigators will recruit up to 20 people with symptomatic knee osteoarthritis. The 20
eligible participants will attend 3 sessions in the laboratory. Session 1 is to collect data
for Aim 1. Sessions 2 and 3 will include the rTMS interventions and data collection for Aim
2.

Aim 1 is a descriptive study to compare the neural (cortical and corticospinal) excitability
of the quadriceps in the symptomatic knee to the asymptomatic knee in participants with knee
osteoarthritis. The investigators will examine the associations between neural excitability
and clinical measures of pain, strength, function, and coping styles.

Aim 2 is a double blind, crossover study design. Each participant will partake in two testing
sessions, spaced 1 week apart. The investigators will evaluate outcome measures prior to and
following the "true" intervention versus the "sham" intervention. The true intervention is
rTMS + exercise. The sham is sham rTMS + exercise. The primary outcome measures are
quadriceps strength, as measured from a maximal isometric voluntary contraction, and
quadriceps activation percent, as calculated from the torque values from the voluntary
strength measurement and a brief, intense electrical stimulus. Secondary measures evaluate
effects of the intervention on 1) clinical measures of pain and functional performance, 2)
corticospinal excitability, and 3) intracortical inhibition and facilitation.

Inclusion Criteria:

- symptomatic knee osteoarthritis primarily involving one leg based on Western Ontario
and McMaster Universities Arthritis Index (WOMAC) function subscale score > 10 (out of
100 points, indicating most dysfunction)

- diagnosis of knee osteoarthritis

- opposite knee with WOMAC pain score ≤ 5.

- opposite knee does not have a diagnosis of knee osteoarthritis

Exclusion Criteria:

- conditions affecting the leg other than osteoarthritis;

- conditions that limit exercise tolerance such as a heart condition

- pregnant or planning to become pregnant in the next 3 months

- conditions that alter sensation and pain processing

- BMI > 35

- severe arthritis in both knees

- history of leg or back surgery in the past year or knee replacement surgery;

- injection in the knee joint in the past 4 weeks

- requires an assistive device to walk

- any contraindications for TMS or rTMS (seizures, metal implants in head, brain related
conditions, brain injury, drug or alcohol withdrawal)

- medications that lower seizure threshold

- history of fainting spells (syncope) or low blood pressure

- sleep deprived

- inability to understand and repeat back directions regarding the study