Lumosity (also known as Lumos Labs) was founded in 2005 by Kunal Sarkar, Michael Scanlon and David Drescher. Lumosity.com launched in 2007 and as of November 2013, has over 50 million members. Lumosity’s mobile app has been downloaded more than 10 million times and "is often at the top of the Apple iTunes Store’s educational-gaming category."
There is no scientific consensus on the benefits of brain training for medical conditions in the clinical environment. Studies of Lumosity's effectiveness have shown mixed results.
Some have shown benefits from the use of Lumos Labs cognitive training:
Dr. Shelli Kesler and colleagues at Stanford University found improved cognitive performance and corresponding increases in brain activity in the pre-frontal cortex in survivors of childhood cancer following training with Lumosity. Participants who trained with Lumosity showed significantly improved processing speed, cognitive flexibility, verbal and visual declarative memory scores.
Kesler et al. demonstrated enhanced math skills and cognitive performance with corresponding changes in brain activity in individuals with Turner syndrome following training with Lumosity.
Kesler et al. found that women whose breast cancer had been treated with chemotherapy demonstrated improved executive function, such as cognitive flexibility, verbal fluency and processing speed after Lumosity training. This work is published in Clinical Breast Cancer. 
Psychologist Maurice Finn and Skye McDonald from the University of New South Wales found that patients with mild cognitive impairment (MCI) who trained with Lumosity improved their sustained attention relative to controls. MCI is considered a precursor condition to Alzheimer’s disease, and this is the first report of cognitive enhancement with training in this population.
However other studies had mixed results, "there is no scientific evidence to support a range of manufacturers' claims [including Lumosity's] that the gadgets can help improve memory or stave off the risk of illnesses such as dementia." A careful attempt to replicate the preliminary experimental results on which this enterprise is based found no effect from the training. Some have also noted that the clinical trials cited on their website show that studies conducted used a very small sample size and that the methodology section fails to clearly explain how control groups were handled. Other studies have failed to demonstrate generalizable benefits of brain training.
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