Neurological symptoms persist in majority of long-haulers
University of California - San Diego
The
first round of results, published June 15, 2022 in Annals of Clinical
and Translational Neurology, revealed the prevalence of various short- and
long-term symptoms and found that, while many patients showed improvement, the
majority still had some neurological symptoms after six months. A subset of
individuals also exhibited significant coordination and cognitive issues, which
had not been previously described.
Following
mild-to-moderate SARS-CoV-2 infections, 56 persons with neurological symptoms
were recruited to the study between October 2020 and October 2021. They
completed a neurological exam, cognitive assessment, self-reported
questionnaires and an optional brain scan. Baseline measurements were taken a
few months after their initial infection and repeated three and six months
later.
At the time of their first visit, 89 percent of participants were experiencing fatigue and 80 percent reported headaches. Other common neurological symptoms included memory impairment, insomnia and decreased concentration. Eighty percent of participants said these symptoms impacted their quality of life.
When
participants returned for their six-month follow-up, only one-third reported
complete resolution of symptoms. The other two-thirds of participants reported
persistent neurological symptoms, though most had diminished in severity. The
most prevalent symptoms at six months were memory impairment and decreased
concentration.
The
authors noted that none of the individuals with persistent symptoms at six
months had any history of pre-existing neurological conditions prior to their
SARS-CoV-2 infections.
"It's
encouraging that most people were showing some improvement at six months, but
that wasn't the case for everyone," said senior author Jennifer S. Graves,
MD, PhD, associate professor at UC San Diego School of Medicine and neurologist
at UC San Diego Health. "Some of these participants are high-level
professionals who we'd expect to score above average on cognitive assessments,
but months after having COVID-19, they're still scoring abnormally."
Researchers
were also surprised to find a novel phenotype within the cohort. Seven percent
of participants displayed a previously unidentified set of symptoms that
included cognitive deficits, tremor and difficulty balancing. The authors
labeled the phenotype Post-Acute Sequelae of COVID-19 infection with Tremor,
Ataxia and Cognitive deficit (PASC-TAC).
"These
are folks who had no neurological problems before COVID-19, and now they have
an incoordination of their body and possible incoordination of their
thoughts," said Graves. "We didn't expect to find this, so we want to
get the word out in case other physicians see this too."
Researchers
are still investigating how much the SARS-CoV-2 virus directly invades the
brain, but Graves said it is more likely that these delayed neurological
symptoms are caused by the infection triggering an inflammatory autoimmune
response in the brain.
The
team plans to continue monitoring participants' symptoms annually for up to 10
years. Additional efforts will evaluate how different COVID-19 variants and
vaccines affect long-term neurological symptoms.
"To have people's cognition and quality of life still impacted so long after infection is something we as a society need to be taking a serious look at," said Graves. "We still need to know how common this is, what biological processes are causing this, and what ongoing health care these people will need. This work is an important first step to getting there."