PLAINVILLE -- Inside the mind of Toren Hall lies limitations, yet compensations.

His autism has affected him socially, yet he readily develops emotional attachments.

Retardation has delayed him intellectually, and hearing and vision impairments have restricted his learning, yet he has a natural ear for music, and the genius to make a piano sing.

The label of autistic savant fits this personable 40-year-old who hears a song once and can then play it back on the keyboard without missing a beat.

Since his childhood when autism took hold, he has been part of the rare group of people with extraordinary gifts. `` His whole life centers on musical stimulation. If he is not playing, he is listening to recordings,'' said Dom Marabello, program coordinator at the group home in Plainville that is run by Amego, an agency that serves people with autism and mental retardation.

Hall has resided at the group home for several years, and was there in 1996 when The Sun Chronicle first profiled him.

He is still there, spending every moment he can in the music room the staff created in the lower level of the raised-ranch house in a rustic section of town.

The organ he once used to pound out tunes has long since broken, Marabello said, and the agency is now looking to replace it, hopefully with a donated one.

Marabello hopes to find a church or other entity that may have a used organ they no longer need.

Meanwhile, Hall gets by with a piano, and with a talent not restricted by the fact that his failing eyesight makes him legally blind.

One of his favorite artists, coincidentally, is the blind singer and songwriter Stevie Wonder.

Ask for a tune by Wonder, and Hall will break out in `` You are the Sunshine of My Life.''

Leave him to his own choice, and he'll bang out `` Ain't No Mountain High Enough,'' or `` Raindrops Keep Fallin' on My Head,'' or a bit of jazz.

He loves to be listened to, and quickly connects with the people he sees regularly, like the Amego staff. `` He is very affectionate,'' Marabello said.

Hall's engaging smile and willingness to embrace a visitor may seem to defy the common perception of autism as a condition that causes emotional detachment and withdrawal, yet that is not always the case.

The Autism Society of America describes autism as a developmental disability affecting an estimated 1.5 million adults and children in this country.

It is caused by abnormalities in brain function that impair communication and social interaction, yet it is also a spectrum disorder that affects each individual differently, and to varying degrees of severity.

Many with the condition smile and laugh, show affection and a variety of emotions, and may respond to the environment either positively or negatively.

Because brain development is uneven, some individuals with the disability have an amazing gift in a specific area, such as mathematics, memory or music, despite their severely limited living skills.

Hall fits the description.

Mentally, he is 4 years old and can't even be allowed to go outdoors alone. But musically, `` he is far ahead of anyone else,'' ' said Geoffrey Horace, Amego's program director.

Experts on autism estimate that only about 10 percent of the people with the disorder have these unusual talents, and even rarer are those who can compose their own music, such as Hall.

Marabello has known Hall since the 1990s when he first worked at the group home. He left for another position before recently returning as program coordinator, when he saw how much Hall's talent has progressed.

`` He sounds more polished,'' Marabello said.

Hall has had some help along the way.

During his childhood years in the special education program in the Newton public schools, he was guided by music teachers who were either hired by his family or provided by the school system.

But he already knew how to play, and all the teachers did was hone his skills. They also introduced him to new sounds and instruments, such as the violin a teacher brought in one day that he simply began to play.

As an adult, Hall lived for a while at the Fernald Developmental Center in Waltham, then went to Amego when the state began placing clients in private facilities.

Horace said at one time Hall was attending a musical program in Pembroke, where he was taught various notes to expand his musical horizons, but he benefited only to an extent.

He seems more content to be left on his own.

While he plays, Hall moves to the tune, and although his speech is not clear, he periodically breaks out in song, or in sounds that mimic a musical instrument.

Because he goes his own way while playing, Hall could likely not perform with a group, Marabello said, but he could play publicly if his audience didn't mind his unique versions of songs.

Hall currently attends a daytime work program in Needham, which leaves his evenings and weekends open to pursue his music.

But without the organ he loved, he's been playing less these days.

`` When he had that organ, he played all the time,'' Marabello said.

Limited yet gifted, Hall seems to make the most of what he is.

`` I've always gotten the impression that Toren is quite happy,'' Marabello said.