The ukulele originated in the 19th century as a Hawaiian adaptation of the Portuguese machete, a small guitar-like instrument, which was introduced to Hawaii by Portuguese immigrants, many from Madeira and the Azores. It gained great popularity elsewhere in the United States during the early 20th century, and from there spread internationally.
The tone and volume of the instrument vary with size and construction. Ukuleles commonly come in four sizes: soprano, concert, tenor, and baritone.
There is a growing body of scientific research suggesting that playing and/or learning to play a musical instrument can delay the onset of dementia.
Although research is ongoing, the mental stimulation resulting from playing a musical instrument has been found to build up the "brain reserves", or additional connections between neurons, which increase the resistance to brain deterioration seen in dementia sufferers.
So do your old folks a favour - buy them a beginners ukulele. The benefits in terms of resistance to dementia onset are seen even for beginners, and who knows, they might even have fun playing the uke!