In 1961 children's charity Action Medical Research funded the late Reg Maling and Derek Clarkson at Stoke Mandeville to develop 'Patient Operator Selector Mechanisms' (POSM). 

Paralysed patients at that time used whistles from their beds to attract the attention of medical staff. Maling and Clarkson felt that if patients were able to control the air in their mouths to blow a whistle, then the same process could be used to operate micro-switches enabling them to control electrical appliances. 

Within six months of the charity grant award, the first POSM instrument was made – giving the patient control over bells, lights, radios, telephones and televisions. Reg Maling spoke to the charity in 2004 - 

"We made a real difference. I remember one lady who had literally only a flicker of movement in one toe. She went on to write a beautiful book of poems – it was quite extraordinary."

The charity also funded Stoke Mandeville's trailblazer Dr Ludwig Guttmann, knighted in 1966 for his pioneering work to rehabilitate patients through sport.  He was awarded a grant from Action Medical Research in 1965 to continue work on POSM.

A company was subsequently set up to develop and manufacture the equipment – and Possum Ltd still exists today, winning the Queen's award for innovation in 2009. 'Possum' in Latin means 'I can'.

Dame Hannah's Trust in Devon offer facilities for children and young adults with complex physical disabilities. Around 44 young people from Dame Hannah's have regular access to POSSUM equipment in the assessment centre. Nellie Dadge is the Occupational Therapist there. She says -

"Matthew, now 22, likes to open the door and drive in to the room in his powered wheelchair. Using the POSSUM controller, he turns off the lights, opens the window and puts the ceiling fan on. Then he can just chill out. Sometimes he chooses to turn the TV on. He is really developing skills in sequencing and likes being in control when he is in the room. It is very empowering for him."

For more information:

http://www.action.org.uk/press_release/patient_operator_selector_mechanisms_i_can