04/19/2013 at 05:30 AM EDT
The multi-talented TV and movie veteran Dick Van Dyke
has canceled public appearances planned for next week, his rep tells Entertainment Tonight
Citing "fatigue and lack of sleep resulting from symptoms of a yet-to-be diagnosed neurological disorder," Van Dyke, 87, will remain in his home in Malibu, with his wife Arlene
, and not fly east for a scheduled ceremony at Manhattan's 92nd Street Y, according to spokesman Bob Palmer.
Seeking advice from anyone with a suggestion, Van Dyke posted on his Twitter account
this week: "My head bangs every time I lay down. I've had every test come back that I'm perfectly healthy. Anybody got any ideas?"
He also said, "It has been going on for 7 years. I've had every test you can think of, including an MRI and spinal tap."
The Y was planning to present Van Dyke with the institution's first Lifetime Achievement Award for Bettering Humanity through Comedy. Earlier this year, Van Dyke received the Screen Actors Guild's highest honor
, its Life Achievement Award.
In addition to starring on TV's top-rated The Dick Van Dyke Show
and Diagnosis: Murder
, and in the popular 1960s movies Bye Bye Birdie, Mary Poppins
and Chitty Chitty Bang Bang
(he also starred in Birdie
in its original Broadway production), Van Dyke has spent the past 20 years committed to volunteer work at the Midnight Mission, a century-old downtown Los Angeles shelter for the troubled and homeless.
He has also helped raise millions of dollars for their new building program and would be on the premises without fail every Thanksgiving, Christmas, Easter and times in between to offer his comfort and support.