• pregnancy or lactation: * pregnant persons will not be included in this study for the following reasons: * there is not sufficient data surrounding the hormone cycle changes during pregnancy and its effects on the condition being studied (pcd). the results could be skewed due to pregnancy. * of note, there are no risks for pregnant persons to participate. according to the device manufacturer, the following contraindications will be followed during the screening process: * patients with an active implantable medical device, such as a cardiac pacemaker, heading aid implant, or any implanted metallic or electronic device * patients with a history of baseline cardiac disease or atherosclerotic cardiovascular disease, including congestive heath failure (chf), known severe coronary artery disease or recent myocardial infarction (within 5 years) * patients with diagnosed bradycardia * patients who have had surgery to cut the vagus nerve in the neck (cervical vagotomy) patients diagnosed with narrowing of the arteries (carotid atherosclerosis) * patients whose pain syndromes are undiagnosed * pediatric patients * pregnant women

• pregnancy or lactation: * pregnant persons will not be included in this study for the following reasons: * there is not sufficient data surrounding the hormone cycle changes during pregnancy and its effects on the condition being studied (pcd). the results could be skewed due to pregnancy. * of note, there are no risks for pregnant persons to participate. according to the device manufacturer, the following contraindications will be followed during the screening process: * patients with an active implantable medical device, such as a cardiac pacemaker, heading aid implant, or any implanted metallic or electronic device * patients with a history of baseline cardiac disease or atherosclerotic cardiovascular disease, including congestive heath failure (chf), known severe coronary artery disease or recent myocardial infarction (within 5 years) * patients with diagnosed bradycardia * patients who have had surgery to cut the vagus nerve in the neck (cervical vagotomy) patients diagnosed with narrowing of the arteries (carotid atherosclerosis) * patients whose pain syndromes are undiagnosed * pediatric patients * pregnant women

• pregnancy or lactation: pregnant persons will not be included in this study for the following reasons: there is not sufficient data surrounding the hormone cycle changes during pregnancy and its effects on the condition being studied (pcd). the results could be skewed due to pregnancy. of note, there are no risks for pregnant persons to participate. according to the device manufacturer, the following contraindications will be followed during the screening process: patients with an active implantable medical device, such as a cardiac pacemaker, heading aid implant, or any implanted metallic or electronic device patients with a history of baseline cardiac disease or atherosclerotic cardiovascular disease, including congestive heath failure (chf), known severe coronary artery disease or recent myocardial infarction (within 5 years) patients with diagnosed bradycardia patients who have had surgery to cut the vagus nerve in the neck (cervical vagotomy) patients diagnosed with narrowing of the arteries (carotid atherosclerosis) patients whose pain syndromes are undiagnosed pediatric patients pregnant women

• pregnancy or lactation: pregnant persons will not be included in this study for the following reasons: there is not sufficient data surrounding the hormone cycle changes during pregnancy and its effects on the condition being studied (pcd). the results could be skewed due to pregnancy. of note, there are no risks for pregnant persons to participate. according to the device manufacturer, the following contraindications will be followed during the screening process: patients with an active implantable medical device, such as a cardiac pacemaker, heading aid implant, or any implanted metallic or electronic device patients with a history of baseline cardiac disease or atherosclerotic cardiovascular disease, including congestive heath failure (chf), known severe coronary artery disease or recent myocardial infarction (within 5 years) patients with diagnosed bradycardia patients who have had surgery to cut the vagus nerve in the neck (cervical vagotomy) patients diagnosed with narrowing of the arteries (carotid atherosclerosis) patients whose pain syndromes are undiagnosed pediatric patients pregnant women