Among the key findings:

Almost a third (31 percent) of respondents reported that they were the first to voice concerns about a grandchild’s developmental delays.

Seventy-two percent said they’re involved in making treatment decisions for their grandchildren.

More than 36 percent said they provided at least some level of “direct care” for an autistic child at least once a week, while 18 percent said they were their grandchild's primary babysitter.

Nearly one in five reported that they and their adult children had moved closer to each other so that the grandparents could help the family manage all that is involved with the child's ASD.

Grandparents help financially, too. About 25 percent of respondents reported spending up to $99 a month to help meet their grandchild's needs. Some said they contribute as much as $1,000 a month, often for such things as therapeutic toys or recreational activities.

Often, they do so at great sacrifice, the survey found. More than 22 percent of grandparents reported going without something so they could help out their grandchildren. Others said they put their own financial security in jeopardy, with 11 percent raiding their retirement funds and 8 percent borrowing money to help with autism-related expenses.

The Interactive Autism Network, which is affiliated with the Kennedy Krieger Institute, is an online project that gathers information from families affected by the developmental disorder.  Director Dr. Paul Law said that his group decided to conduct the survey after hearing from families how involved grandparents are in their autistic grandchildren's lives.