Dr. Fong's area of clinical expertise is cognitive disorders related to aging, including dementia and delirium. Throughout her career, she has made significant contributions and advances in patient care and research. Her goal and the main focus of her work is to reveal causes and advance treatments of cognitive decline and dementia. Her clinical activities include an outpatient clinic in the Cognitive Neurology Unit at Beth Israel Deaconess Medical Center where she evaluates and treats patients with Alzheimer's disease, diffuse Lewy body disease, fronto-temporal dementia, vascular dementia, and mild cognitive impairment. She also directs the cognitive clinic within the Beth Israel Deaconess Medical Center COVID-19 Survivorship Program.

Dr. Fong’s investigative work is focused on the possibility that delirium is a potentially reversible contributor to cognitive decline and dementia in the elderly. As an investigator in the Successful Aging after Elective Surgery (SAGES) study, an NIA-sponsored Program Project Grant (Inouye, PI), Dr. Fong has published on the neuropsychological profiles of older adults in relationship to cognitive performance and delirium and looked at outcomes of patients with mild cognitive impairment undergoing surgery.  Most recently, the interface between delirium and dementia has become a major focus of Dr. Fong’s work, which focuses on plasma neuronal injury and Alzheimer’s disease biomarkers as predictors of delirium and long-term cognitive decline and exploring shared pathophysiology between delirium and dementia.