Filipino boxing champion Manny Pacquiao denied he has Parkinson's disease. He clarified his medical status in response to a report by Forbes which cited a prominent Filipino doctor's observation that the eight-division world champion's movements are early indicators of the ailment.

Besides the opinion of neurologist Dr Rustico Jimenez, president of the Private Hospitals Association of the Philippines, there are speculations about the future of Pacquiao in boxing after his December loss to Mexican boxer Juan Manuel Marquez in their fourth bout which resulted in the Filipino boxer's fifth loss in his career.

Mr Jimenez cited movements in Pacquiao's hands as the basis for his opinion, although he admitted he has never examined the boxer in person.

Previously, Dr Raquel Fortun, the number one forensic pathologist in the Philippines, had expressed alarm over the result of Pacquiao's CT scan after his loss to Marquez. "When the brain gets shook like that, it's very dangerous . . . Since it's not truly fixed to your sill, when your brain gets shaken, there are connections that get cut off, and you get small hemorrhages," The Inquisitr quoted the pathologist.

"The statements by the doctors show a total lack of ethics and it was irresponsible. This was just personal opinion and there were no medical tests," Pacquiao said in a press release from Israel where he is on vacation with his family.

The boxer also told GMA News that he had undergone at a U.S. hospital medical examination, including MRI, after his bout with Marquez and he was cleared of Parkinson's disease which has victimised many boxers before him.

But it is not just boxers who get the disease. Even actors like Back to the Future star Michael J Fox are also afflicted with Parkinson's.

However, it is a fact that many boxers and other amateur and professional athletes suffer from Parkinson's diseases because of the repeated concussions they suffer during the course of their boxing career.

Medical experts said it takes 12 to 16 years after the start of a career in boxing that symptoms and signs of dementia pugilistica develop progressively. DP's manifestations include dementia or declining mental ability and problems with memory, and Parkinsonism or tremors and lack of coordinators.

There are a number of boxers who have been confirmed to be suffering or had suffered from Parkinson's such as:

1. Freddie Roach - The current trainer of Pacquiao and who was a professional boxer from 1978 to 1986. Here is a video clip of his bout with American boxer Joe Ruelaz in 1984.

2. Sugar Ray Robinson - He was named greatest fighter of the 20th century by the Associated Press and greatest boxer in history by ESPN in 2007. He died in 1989 in poverty at the age of 67. Here is a video clip of his fight versus Jake LaMotta.

3. Joe Frazier - His professional career lasted 21 years from 1965 to 1976 and he holds the record for defeating Muhammad Ali on points in the Fight of the Century in 1971. Here is a clip of that bout.

4. Muhammad Ali - The first and only three-time lineal World Heavyweight Champion and is called The Greatest. He was recognised as the Sportsman of the Century by Sports Illustrated in 1999 and Sports Personality of the Century by BBC. His doctor, Ferdie Pacheco, insisted that Ali does not have Parkinson's disease but Parkinson's Syndrome. Here is a video clip of Ali's Thrilla in Manila bout.

While Pacquiao's mother, Dionesia, and wife, Jinkee, have urged him to retire from boxing, the champ reportedly wants to engage Marquez in a fifth face off, while boxing organisers are still hoping the Filipino champ would also fight Floyd Mayweather Jr before he hangs up his gloves for good.