World Health Organization (WHO) has previously linked the Zika virus to the development of the autoimmune disorder Guillain-Barré syndrome in adults and microcephaly in expecting mothers, but a new study suggests that Zika virus can also cause another brain disease in adults.

The new neurological disorder associated with Zika virus is the acute disseminated encephalomyelitis (ADEM). ADEM, according to the National Institute of Neurological Disorders and Stroke, is sometimes mistakenly diagnosed as a severe first attack of Multiple Sclerosis due to similar symptoms and appearance of the white matter injury on a brain scan.

As opposed to the Guillain-Barré syndrome, which attacks peripheral nerves outside the brain, ADEM attacks the Central Nervous System-brain and spinal cord. It ADEM causes severe swelling in the brain and spinal cord resulting in the damage of myelin, the white protective coating that surrounds nerve fibers.

For the study, researchers analyzed 151 patients that visited Restoration Hospital in Recife, Brazil showing symptoms of arboviruses between December 2014 and Jun 2015, according to Reuters.

Among those patients, six developed neurological symptoms either right away or within 15 days after being tested positive for Zika virus. Of the six, four had Guillain-Barré syndrome while the remaining two developed ADEM.

News Week reported that all six patients suffered from neurological complications in their follow-ups. Five of them reported loss in motor functions, one experienced visual problems while difficulty in cognitive and memory function was seen on one of the patients.

In a report from the Guardian, Dr. Maria Lucia Brito Ferreira of the Restoration hospital and author of the study said, "Though our study is small, it may provide evidence that in this case the virus has different effects on the brain than those identified in current studies,"

"However, our study may shed light on possible lingering effects the virus may be associated with in the brain," she added.

The study was presented on Sunday at the annual conference of the American Academy of Neurology in Vancouver.