A group of scientists says that neurological damages caused by high-frequency sounds are not possible in today's technology.

They draw such conclusion after recent reports of an alleged sonic attack were made by U.S. government officials in Cuba.

In an open letter published in The Guardian, 15 signatories from renowned research and academic institutions in the United States, England, The Netherlands, Germany, and Cuba disputed claims that a sonic attack has caused neurological harm to American diplomats stationed in China.

This incident mirrors related cases of diseases acquired by 24 U.S. government officials in Cuba that were reported in late 2016. The reports stirred hysteria and prompted scientists to conduct an investigation.

Nature Of The Sonic-Induced Neurological Damage

In a U.S. government-commissioned study published in JAMA, researchers tested the U.S. diplomats stationed in Cuba to determine if the high-frequency sounds they heard have lasting detrimental effects on their health.

It was found that the subjects had balance and thinking problems, difficulty in sleeping, and headaches. Some of the test participants had widespread injuries in the brain, but some scientists contend this finding.

Andrew Oxenham, a professor in the departments of psychology and otolaryngology at the University of Minnesota in Minneapolis, explained that very high or very low-frequency ultrasound tends to decrease over distance. This means that a possible sonic attack should have massive loudspeakers, which is impossible to house in today's smaller devices.

Timothy Leighton, a professor of ultrasonics and underwater acoustics at the University of Southampton in England, have found evidence of ultrasound in places where the subjects experienced the so-called sonic attacks. However, he said symptoms such as headaches and nausea are only accidental.

"As a result, people got the impression this was some sort of ultrasonic death rifle," Leighton said.

Cognitive Impairments That Everybody Has

In a letter published May 18 in the Journal of Neurology, Sergio Della Sala and Robert McIntosh said the neurological and cognitive symptoms exhibited by American diplomats in Havana have undetermined causes.

Six of the 21 employees who underwent neuropsychological battery tests showed impairment in at least one of the 10 cognitive domains. This means that 40 percent of the subjects performed at or below the 40th percentile on any given task.

"Concerns over possible 'health attacks' have led to the ongoing withdrawal of staff from the US embassy in Havana," the authors wrote.

The researchers, who are both professors and researchers at the University of Edinburgh in the UK, concluded that everyone could practically exhibit the same cognitive symptoms as reported by the United States embassy employees.

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