Persistent smell loss that can include diminished or distorted smell function is a common symptom of long COVID syndrome. There are limited treatment options for long COVID-related smell loss. Our study aims to determine the efficacy of two at-home treatments, smell training and non-invasive trigeminal nerve stimulation. This study requires participants to conduct daily at-home treatment sessions, attend three in-person study visits at the MUSC Department of Psychiatry and Behavioral Sciences, and complete electronic questionnaires over the 12-week trial, and again at the six-month timepoint. Participants in this trial may benefit directly with an improvement in sense of smell. However, participation may also help society more generally, as this study will provide new information about long COVID-related smell loss and its treatment.

EEG Substudy:

Long COVID syndrome has been associated with cognitive impairment and may be related to affected emotional regulation. This study will use a electroencephalography (EEG) to examine how the body and brain responses to emotional cues in participants who are currently undergoing treatment for COVID-related smell loss. Participation will aid in the understanding of how emotional processing in long COVID is impacted by treatment for related smell loss.

Blood Analysis Substudy:
Alzheimer's Disease can be precedented by other clinical disorders or neuropsychiatric symptoms. Due to the cognitive deficits that can affect those with Long COVID, this sub study will use a blood sample to investigate if there are blood based biomarkers for Alzheimer's in those who report Long COVID symptoms.

Smell loss has been reported in more than 50% of older adults. Currently there are no validated methods for classifying patients with smell loss in aging based on either disease site or process. This study aims to better understand how age affects the sense of smell. This study will involve those 50 and older and will take up to 5 years, with 5 follow up annual visits, or can be done remotely.

The main objective of this project is to develop a quick and efficient screening instrument to accurately identify individuals with olfactory dysfunction (from all causes of olfactory dysfunction). We hope to systematically develop an olfaction screening instrument that is highly correlated to objective olfaction, as currently, this does not exist. Our overall hypothesis is that we can reliably predict an abnormal objective olfaction score using the screening instrument we develop.