VOA健康报道--研究发现感染新冠即便轻症也会改变大脑结构

Study: Even Mild COVID-19 Cases Linked to Brain Changes

A new study provides additional evidence that COVID-19 can damage parts of the brain.

The study said that even people with mild sickness can suffer brain tissue shrinkage and damage to areas that control smell.

The research was led by scientists at Britain's Oxford¹ University. The researchers said their study provides "strong evidence" of "brain-related abnormalities in COVID-19."

The team noted² that past studies have also found links between COVID-19 and changes to the brain. But those studies centered mainly on COVID-19 patients who were hospitalized with severe sickness.

The latest study recently appeared in the publication Nature.

The team said further study is needed to find out whether the brain changes are long lasting³ and can be fixed⁴.

The study involved 785 subjects in Britain between the ages of 51 and 81. All were given two brain scans to measure differences during the experiment. A total of 401 subjects were found to be infected with COVID-19 between the scans. Most of them had only minor⁵ sickness.

The researchers reported a number of brain effects in the patients. The subjects experienced the effects, on average, four-and-a-half months after infection.

The changes included "a greater reduction in gray matter thickness" after individuals were infected with COVID-19. Gray matter in the brain helps people control movement, memory and emotions. The greatest reduction was seen in areas of the brain linked to smell. In addition, some infected patients also showed "a reduction in whole brain size," the researchers reported.

On average, subjects infected with COVID-19 also showed "greater cognitive⁶ decline" linked to an area of the brain related to cognition.

Gwenaëlle Douaud is a professor at Oxford and the lead writer of the study. She said in a statement that losses in gray matter and the tissue damage in infected individuals led to a reduction in their abilities to perform complex tasks.

"All these negative effects were more marked at older ages," Douaud noted. "A key question for future brain imaging studies is to see if this brain tissue damage resolves over the longer term," she added.

The study was carried out when the Alpha version of COVID-19 was widespread in Britain. Past studies have found that some COVID-19 patients suffered from "brain fog," or a lack of mental clarity. The condition can cause memory problems and reduce a person's ability to be attentive⁷, concentrate and process information normally.

The researchers did not say whether vaccination⁸ against COVID-19 had any influence on the brain changes. But the UK Health Security Agency said released findings on the issue last month. The agency said an examination of 15 studies found that vaccinated⁹ people were about half as likely to suffer long-term effects of COVID-19 compared with unvaccinated people.

Words in This Story

scan – v. to use a special machine to read or copy (something, such as a photograph or a page of text) into a computer

decline – v. to refuse something

cognition – n. the use of conscious metal processes

task – n. a piece of work to be done

negative – adj. bad or harmful

concentrate – v. to direct attention or efforts toward a particular activity, subject or problem

1 Oxford   

n.牛津（英国城市）

参考例句：

• At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
• This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。

2 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

3 lasting   

adj.永久的，永恒的；vbl.持续，维持

参考例句：

• The lasting war debased the value of the dollar.持久的战争使美元贬值。
• We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。

4 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

5 minor   

adj.较小(少)的，较次要的；n.辅修学科；vi.辅修

参考例句：

• The young actor was given a minor part in the new play.年轻的男演员在这出新戏里被分派担任一个小角色。
• I gave him a minor share of my wealth.我把小部分财产给了他。

6 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

7 attentive   

adj.注意的，专心的；关心(别人)的，殷勤的

参考例句：

• She was very attentive to her guests.她对客人招待得十分周到。
• The speaker likes to have an attentive audience.演讲者喜欢注意力集中的听众。

8 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

9 vaccinated   

[医]已接种的，种痘的，接种过疫菌的

参考例句：

• I was vaccinated against tetanus. 我接种了破伤风疫苗。
• Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗？