Clinical Focus

  • Sleep Medicine

Academic Appointments

Professional Education

  • Board Certification, American Board of Psychiatry and Neurology, Sleep Medicine (2017)
  • Board Certification, American Board of Psychiatry and Neurology, Neurology (2015)
  • Fellowship, Stanford University, Sleep Medicine (2016)
  • Residency, UT Southwestern Medical Center, Neurology (2015)
  • M.D., UT Southwestern Medical Center, Medicine (2011)

All Publications

  • Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease. Chronobiology international Geng, Y. J., Smolensky, M. H., Sum-Ping, O., Hermida, R., Castriotta, R. J. 2022: 1-30


    Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

    View details for DOI 10.1080/07420528.2022.2080557

    View details for PubMedID 35758140

  • Phases of the Diagnostic Journey: A Framework International Archives of Internal Medicine Geng, L., Sum-Ping, O., Geng, Y. 2019
  • Pathogenesis of Hypersomnia Reference Module in Neuroscience and Biobehavioral Psychology Sum-Ping, O., Darby, C., Guilleminault, C. 2017
  • Kleine-Levin Syndrome CURRENT TREATMENT OPTIONS IN NEUROLOGY Sum-Ping, O., Guilleminault, C. 2016; 18 (6)


    Kleine-Levin Syndrome [KLS] is often under-recognized and also misdiagnosed. When suspicion for KLS is raised, a thorough clinical evaluation should be performed, including detailed history from family members and a neurologic and psychiatric examination. Additional studies may include PSG, EEG, neuroimaging, as well as serological and CSF studies to rule out alternative diagnoses as clinically indicated. After arriving at a diagnosis of KLS, the foundation of care is supportive. Patients and their families should be provided with education about the disease. During symptomatic periods, patients should be allowed to rest at home under caregiver supervision. Caregivers should pay special attention to the patient's eating habits and mood. Patients should not be allowed to drive or operate heavy machinery during these episodes. In between episodes, avoidance of reported triggers, such as alcohol and infection are encouraged as is maintenance of a regular sleep-wake cycle. Pharmacologic therapy has not been well-studied and for most patients is not necessary. For more severe cases, targeted symptomatic therapy, such as modafinil or amantadine for somnolence or risperidone for psychosis may be considered depending on the patient's symptomatology. Lithium has the best data to support its use as a prophylactic agent and for patients with severe or frequent episodes, may be considered.

    View details for DOI 10.1007/s11940-016-0409-2

    View details for PubMedID 27073070