Even when sitting 'bolt upright' , which my wife finds difficult to do because of curvature of the spine caused by lifting heavy patients long before lifting aids were introduced, there is a gap of several inches between her head and the head restraint.

Is there an accessory on the market which could be fitted to the front of the head restraint so as to fill the gap and provide her with the support which she would need in the event of a crash so as to avoid whiplash injury?