Who can forget the smell of lemon or the feel of sandpaper? They're both powerful stimuli that make a strong impression. Those strong impressions were both part of a sensory enrichment program that helped autistic boys gain a better foothold in the world around them.

Boys who took part in an enrichment program that used the scent of lemons and feel of sandpaper to stimulate their sensory systems improved in both behavior and cognitive function. They not only tested better, their parents also saw the improvement in their everyday life.

Among the children in the enrichment group, 42% improved five points or more on the Childhood Autism Rating Scale. Only 7% of the children in the standard group showed this improvement.

Children with autism typically have sensory problems, most commonly with smell and touch sensitivity. Research in animals suggested that environmental enrichment would have a beneficial effect on autistic children, but until now this hasn't been tested.

The study involved 28 autistic boys aged 3-12. They were placed in two groups balanced for age and autism severity. For six months, both groups participated in standard autism therapies, but one group also had daily sensory enrichment exercises in touch, smell, feel, sight and movement, what the researchers call environmental enrichment.

Parents of the boys in the enrichment group received a kit that contained items designed to stimulate the senses. Essential oils — including apple, lavender, lemon and vanilla — engaged their sense of smell. For touch, there were squares of plastic doormat, smooth foam, a rubber mat, aluminum, felt, sponges and of course, fine sandpaper. The kit also contained pieces of carpet, hard flooring, pillows, cardboard and bubble wrap that parents placed on the floor to create a multi-textured walking path for the children.

Children were also given items to move about and manipulate, including a piggy bank with plastic coins, a small fishing pole with a magnetic hook and miniature plastic fruits.

Many household items were also used, including bowls to hold water at different temperatures for the child to dip a hand or foot in and metal spoons that parents would warm or cool and touch to the child's skin.

Parents were instructed to conduct two sessions a day lasting 15-30 minutes each. In each session, there would be four to seven different exercises using kit and household items to provide stimuli for touch, sight, smell, movement and temperature. The children also listened to classical music once a day.

The sensory focused treatment appeared to do the children a world of good.

After six months, 42% of the children in the enrichment group improved 5 points or more on the Childhood Autism Rating Scale, a test which measures behaviors such as how the children relate to people and respond to sights and sounds. Only 7% of the children in the standard group showed this improvement.

On the Leiter-R Visualization and Reasoning test, scores of the enrichment children rose while those of the standard group fell. At the end of the study, the enrichment children averaged 11.3 points higher than the children who received standard treatment.

Perhaps most importantly, 69% of the parents of children in the enrichment group reported improvement in their children at the end of the study, while only 31% of the parents of the children receiving standard care reported this.

Because many of the items used in the study are commonly available in the home, this therapy could be a practical, low-cost option for many parents of children with autism.

Most current therapies for autism must be started at a very young age to be effective, whereas in this study, environmental enrichment worked for boys up to age 12. The researchers are now conducting a larger randomized clinical trial that includes girls that they hope will confirm the effectiveness of environmental enrichment and show that it's not just for boys.

The study is published online in Behavioral Neuroscience and will also appear in a future print issue of the journal.