Internal tremors and vibrations in long COVID: a cross-sectional study
Authors: Zhou Tianna , Sawano Mitsuaki , Arun Adith S. , Caraballo César , Michelsen Teresa , McAlpine Lindsay , Bhattacharjee Bornali , Lu Yuan , Khera Rohan , Huang Chenxi , Warner Frederick , Iwasaki Akiko , Krumholz Harlan M. 
Published: June 2023

ABSTRACTImportanceInternal tremors and vibrations symptoms have been described as part of neurologic disorders but not fully described as a part of long COVID.ObjectiveTo compare demographics, socioeconomic characteristics, pre-pandemic comorbidities, new-onset conditions, and long COVID symptoms between people with internal tremors and vibrations as part of their long COVID symptoms and people with long COVID but without these symptoms.DesignA cross-sectional study, Listen to Immune, Symptom and Treatment Experiences Now (LISTEN), of adults with and without long COVID and post-vaccination syndrome, defined by self-report.SettingHugo Health Kindred, a decentralized digital research platform hosting a network of English-speaking adults interested in contributing to COVID-related research. No geographic limitation applied.ParticipantsThe study population included 423 participants who enrolled in LISTEN between May 2022 and June 2023, completed the initial and the conditions and symptoms surveys, reported long COVID, and did not report post-vaccination syndrome.ExposureLong COVID symptoms of internal tremors and vibrations.Main outcomes and MeasuresDemographics, pre-pandemic comorbidities, and current conditions, other symptoms, and quality of life at the time of surveys.ResultsOf the 423 participants (median age, 46 years [IQR, 38-56]), 74% were female, 87% were Non-Hispanic White, 92% lived in the United States, 46% were infected before the Delta wave, and 158 (37%) reported “internal tremors, or buzzing/vibration” as a long COVID symptom. Before long COVID, the groups had similar comorbidities. Participants with internal tremors were different from others in having worse health as measured by the Euro-QoL visual analogue scale (median: 40 points [IQR, 30-60] vs. 50 points [IQR, 35-62], P = 0.007), having financial difficulties caused by the pandemic (very much financial difficulties, 22% [95% CI, 16-30] vs. 11% [7.3-15], P < 0.001), often feeling socially isolated (43% [95% CI, 35-52] vs. 37% [31-43], P = 0.039), and having higher rates of self-reported new-onset mast cell disorders (11% [95% CI, 7.1-18] vs. 2.6% [1.2-5.6], Bonferroni-adjusted P = 0.008) and neurologic conditions (including but not limited to seizures, dementia, multiple sclerosis, Parkinson’s disease, neuropathy, etc.; 22% [95% CI, 16-29] vs. 8.3% [5.4-12], Bonferroni-adjusted P = 0.004).Conclusions and RelevanceAmong people with long COVID, those with internal tremors and vibrations have several other associated symptoms and worse health status, despite having similar pre-pandemic comorbidities, suggesting it may reflect a severe phenotype of long COVID.KEY POINTSQuestionDo people with long COVID symptoms of internal tremors and vibrations differ from others with long COVID but without these symptoms?FindingsIn this cross-sectional study that included 423 adults with long COVID, 158 (37%) reported having “internal tremors, or buzzing/vibration,” had worse quality of life, more financial difficulties, and higher rates of new-onset mast cell disorders and neurologic conditions, compared with others with long COVID but without internal tremors and vibrations.MeaningInternal tremors and vibrations may reflect a severe phenotype of long COVID.