'Sonic attack' impacted 'at least 20 regions' of US diplomat's brain - but cause
 remains unknown, new study finds
[1]https://news.yahoo.com/sonic-attack-impacted-least-20-204353837.html

   Jim Bell's comment:

   Why not use a sound spectrum analyzer, running on a smartphone app, to
   identify this?

References

   1. https://news.yahoo.com/sonic-attack-impacted-least-20-204353837.html