In 1994, the NFL established the Mild Traumatic Brain Injury Committee (MTBI), which was later replaced by the Head, Neck and Spine Committee, to study concussions and brain injuries in professional football players. The committee and its leadership, including Ira Casson and Elliot Pellman, were criticized by former players for stating that there is not enough research to determine if concussions lead to permanent brain injury. Pellman, who served as chairman of the committee from 1994 to 2007, received a large amount of criticism because he did not have a background in neurology and the research he published on brain injuries disagreed with the findings of independent scientists. In 2009, a NFL-commissioned report showed increased incidence of diagnosis of memory loss and dementia among retired professional football players when compared to the general population. The study also indicated that these symptoms were related to the effects of concussions. However, the NFL and the report's own researchers questioned the reliability of some of the data-gathering methods employed by the study, including the fact that the study was conducted by phone. The same year, the committee acknowledged for the first time that concussions can lead to long-term brain injuries. A Congressional hearing in October 2009, as well as pressure from the National Football League Players Association (NFLPA), led to an overhaul of the concussion policy in November and December of that year.