Catastrophic injuries often come with complex physical, cognitive and emotional difficulties that will affect the client's behaviour and communication at different stages of their rehabilitation. Low, medium and high-tech solutions, as well as a no-tech option, are available to replace or supplement the user's own voice. Each has its merits and the client may transition between all four depending upon the environment, subject/context, the communication partner and individual levels of fatigue and motivation.  

A claimant with a significant brain injury might reject all forms of electronic communication until they have come to terms with their situation. An acquired brain injury may, in itself, prevent the client from using complex language and aids. In contrast, following rehabilitation, a client may develop breathing and breath control that leads to the restoration of speech. Only by careful observation and review of the written evidence can the technology expert form a view and describe, what could be, a fluid and evolving situation.

The use of a sophisticated communication aid does not negate the need for low and mid-tech solutions, which might be used where the high-tech aid would be impractical or unduly cumbersome – such as when travelling in a vehicle or relaxing in a comfortable chair. An experienced technology expert will understand the different scenarios and report accordingly.