Shania Twain undergoes tests on her voice

The Canadian country star performed a string of vocal exercises as doctors examined her vocal cords at an American hospital.

'Things look great. Things just seem to be a little tight down there,' Dr. Gaelyn Garrett concluded.

'I think we’re just missing one puzzle piece. That puzzle piece is helping you relax all these muscles all the time.'

Twain, 45, visited the Vanderbilt Dayani Center in Nashville, Tennessee after struggling to project her voice and finding herself unable to perform.

Doctors put a tiny camera inside the singer's throat to zoom in on her vocal cords and try to get to the root of the problem.

Much to Twain’s relief the medics told her she did not have any nodules inside her throat and said there was not any obvious damage.

Instead they told her she was suffering from Dysphonia - a condition where the muscles squeeze the voicebox.

'It's not just my singing voice, it's my any voice,' Twain explained, during scenes which aired on her reality TV show Why Not? With Shania Twain.

'That's all just stemming from plain old fear - stage fright, domestic violence in the home as a child, my parents dying, not knowing what’s next - all these different stages of fear in my life.

'I've just trapped my own voice and now I’ve just got to unwind all that. That’s not going to be solved in one day of therapy with any person to be honest.'