TORONTO -- A growing number of so-called COVID-19 "long-haulers" who believe they had the disease before testing was widely available are complaining of new neurological symptoms including confusion, trouble concentrating and memory loss that persist weeks and even months after their initial sickness.

Ruth Castellanos says she has developed an unnerving tremor in her hands after a suspected COVID-19 infection in mid May

"I'm jolted out of sleep and I feel like my body just vibrates at night," Castellanos said in an interview with CTV News.

Castellanos, who lives in Troy, Ont., said she is no longer able to work as a college instructor as the tremors are just one of the troubling neurological symptoms she suffers from.

Once fit and healthy, Castellanos now describes days where she is confused and has trouble reading.

"I have been experiencing a lot of brain fog and this is what happens I sometimes stutter. I lose my train of thought. I get confused reading. Even simple instructions becomes hard and frustrating. I have to re-read things," Castellanos said.

She says doctors don't know what is causing her neurological symptoms or how to help her.

"Not only am I scared of the unknown, but I'm scared now of what my symptoms are, and there's a lot of confusion inside of me," Castellanos said.

She fears the brain fog and tremors may become her "new normal."

"It's has been very debilitating, and it has been very trying on myself as a person, let alone on my body," Castellanos said.

But Canadian long-hauler patients like Suzie Golding say getting recognition or help from doctors has been difficult.

The Oakville, Ont. resident said contracting the coronavirus has been "a life-altering experience" for her. She says she has been plagued with short-term memory deficits, brain fog and fatigue since developing what appeared to be COVID-19 in March. She is unable to work as a floral designer and the single mom is doing her best to raise her son while battling her illness.

"I'm really just living my life at a very basic level, trying to get through each day with great difficulty," Goulding said. "It's terrible."

In hopes of providing some relief to other long-haulers like herself, Goulding started an online group called COVID Long Haulers Support Group Canada. The support group has over 2,800 members and the numbers are growing.

"A lot of people are having doctors that say to them 'This is just anxiety and we can't help you. There's nothing we can do. You're just anxious,' and really dismissing the fact that… [this] is something that is happening," Goulding said.

The group is also asking the federal and provincial governments to provide more help for those who develop these disabling neurological symptoms.

"We need rehabilitation. We need COVID care clinics set up for us so that we don't have to wait in emergency wards for six to eight hours to be told that there's nothing that they can do for us," Goulding said.

STUDIES UNDERWAY TO LOOK FOR ANWSERS

In two labs in Ontario, Canadian researchers are focusing on this group of patients.

Dr. Adrian Owen, a cognitive neuroscience professor at Western University in London, Ont. suspects that the issue of COVID-19 long-haulers may be greater than initially thought.

"This is something that is ongoing. If these issues are long-term or permanent, we have a very, very large societal and economical problem on our hands," Owen said in an interview with CTV News.

To help address the issue, Owen is part of a team of Canadian neuroscientists who have launched the online COVID-19 Brain Study -- the world's largest project to consider the "direct and indirect effects of the disease on the brain."

The study, launched by Western University and the University of Toronto, provide online tests to 50,000 post-COVID patients worldwide over the course of a year in an attempt to measure their brain function.

Owen explained that the tests are more like online games that last about a minute and a half and assess brain functions including memory, concentration and problem-solving abilities.

"Look at all those pieces of information together and will be able to work out how COVID-19 is affecting cognitive function and whether it's affecting some people more than others," he said.

Owen hopes to have some results from the study early this fall to better understand the effects of COVID-19 on the brain and find ways to help those suffering from neurological symptoms.

In Hamilton, McMaster University scientist Dr. John Connolly is also looking at the impact the novel coronavirus can have on brain function.

"From preliminary research being published around the world, it appears the virus is capable of passing the blood-brain barrier, attacking the brain directly," wrote Connolly in an email to CTV News. He is chair of cognitive neuroscience of language at McMaster.

"This means that many of the complications from the illness, such as lung and other organ failure, may be due to brain dysfunction as opposed to the virus directly attacking these other organs."

Connolly's lab has partnered with McMaster neurotech start-up VoxNeuro and will use electroencephalogram-based (EEG) neuroimaging to assess brain function over time.

Connolly said patient enrollment in the study is expected to begin soon.

"As we specialize in cognitive health, and COVID has been proven to have lasting neurological consequences, we are able to quantify that, and provide data that differentiates between true cognitive decline and perceived decline due to symptoms caused by situational factors, such as stress, general fatigue or mood," Connolly said.

He added that the goal of this study is to better understand what types of patients are most vulnerable to neurological symptoms and which medical interventions are most effective for treatment.

Researchers will be able to draw conclusions from the study in a year but Connolly said they will likely start to see trends in the data within three to six months. However, if more long-haulers participate in the study, then results and possible treatments may come sooner.

"The more patients we can test and the faster we can test them, the faster we can get definitive answers to these questions," Connolly said.

While these symptoms may only affect a minority of COVID-19 patients, Connolly said that reliable neurocognitive assessment procedures will be essential in accurately gauging active and post-COVID patients' cognitive abilities, and in tracking their recovery.

"With the perspective that our world will not return to normal, and that instead we will be living in a post-COVID world from here on, we must understand what we're up against," Connolly said.

"Not just in the short term of mitigating death, but ensuring that life beyond COVID is healthy and meaningful for its survivors."