Court documents obtained by several US outlets claim the musician is suffering from a "major neurocognitive disorder (such as dementia)."

A statement on Wilson's website from his family confirms two family representatives will serve as co-conservators.

The move was made "after careful consideration and consultation" with Wilson, 81, along with his children, doctors and housekeeper, and came after his wife of 28 years, Melinda, died in January.

"Brian will be able to enjoy all of his family and friends and continue to work on current projects as well as participate in any activities he chooses," his family said.

According to court documents first obtained by US site the Blast, Wilson "does not have the capacity to give informed consent to the administration of medications appropriate to the care and treatment of major neurocognitive disorders".

A doctor quoted in the documents said Wilson was "easily distracted, often even when aware of surroundings" and "often makes spontaneous irrelevant or incoherent utterances".

The American musician is "unable to properly provide for his own personal needs for physical health, food, clothing, or shelter", the filing said, noting that his wife used to look after his daily needs.

"Melinda was more than my wife," Wilson wrote following her death.

"She was my saviour. She gave me the emotional security I needed to have a career. She encouraged me to make the music that was closest to my heart. She was my anchor."

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Wilson was previously under a conservatorship in the early 1990s, after his family fought to extricate him from psychologist Eugene Landy, who he had named as chief beneficiary in his will.

She had started working with Wilson in 1975, but became a controlling presense in his life, isolating him from his family.

He previously had a series of nervous breakdowns in the 1960s, with his mental health problems exacerbated by heavy drug use.

Wilson is the co-founder and chief songwriter for The Beach Boys. The Rock And Roll Hall Of Fame band gave birth to the California rock sound in the`1960s

A court hearing to determine whether the conservatorship will go ahead is scheduled for 26 April.