Music training boosts the brain
The study, by McMaster University:

Canadian scientists compared children aged four to six who took piano lessons for a year with those who did not. They found the musical group performed better on a memory test also designed to assess general intelligence skills such as literacy and math's ability.

Researchers at McMaster University in Hamilton used magneto encephalography (MEG) brain-scanning technology to compare the developmental changes in 12 children aged four to six over the course of a year.
The study, to be published in the October edition of Oxford University's neurology journal Brain, found that those who took music lessons showed more changes in brain responses. The study found particular changes in the attentional systems of children who took music lessons, which affected their ability to pay attention to important things around them. Previous studies found kids who learned an instrument had better improvements in IQ scores.

                                                            (MEG Brain Activity)

Positive proof that music is the best mind trainer comes from Oxford University.
Only ten percent of the students there study Piano,yet this ten percent takes 75 percent of all the school prizes and scholarships.That not being the record of a single year, but the average, over a period of 30 successive years.

Piano lessons help children learn how to stay focused and achieve goals.

Piano lessons help children set specific goals and then work towards reaching these goals. Each new piece of music a student learns requires a specific set of skills and playing habits. To achieve these goals students must learn to stay focused and study each note, measure and phrase to understand how to play the song. In doing this students learn to think critically and creatively as they decide how to make the music come to life. Staying focused over time develops good study habits that become natural. This is important because learning to practice good habits that match their goals shows children how to make their dreams come to life!

Harvard University Study

Yes: When learning to play the piano, your child experiences the unique integration of body and mind that music provides. Sensory integration is a crucial factor in childrens learning readiness for school subjects such as reading, writing, and math. Music improves spatial-temporal reasoning, a neurological process needed to understand mathematics.

Many Parents ask:
I want to enroll my child in piano lessons. When should I buy a piano?

Think Johnny and Susie can learn to play piano without one?
Don't hold your breath. Taking piano lessons without a piano is like learning to swim without water. Don't wait to purchase a piano if you have enrolled or are planning to enroll your child in piano lessons. There are many options for every budget. My advice is to get the best instrument you can afford because good pianos hold their value. If your child later decides that piano is not their cup of tea, you can always sell it for about what you paid for it. Another reason to get the best piano you can afford is that quality matters. You can safely compare this to your golf game. How much more fun is it to play with a good set of clubs over a bargain set that lacks power and precision.