It's almost impossible to imagine the strain some families are under as a result of brain injury. The trouble is that it happens suddenly, often in tandem with "real" physical injuries and huge financial pressures. Also, the symptoms can be hard to define.
Balance, speech, memory, sight and spatial skills can be affected. Those suffering from brain injury may have difficulty processing information and thinking things through. They may be unable to control their behaviour. They can lose their social skills: say things one would not normally say and act in an inappropriate way, laugh a little too long, be abusive or use crude language.
They can be irritable, impatient and self-centred. They may lose all initiative. They may suffer from mood swings, anxiety, frustration, anger, depression and fatigue, or be unable to control their emotions. They can find children difficult to be around. In fact, their personalities may change completely.
"Even with mild head injury, you've often got attention and concentration problems," says Dr Deirdre McMackin, senior clinical neuropsychologist at Beaumont Hospital in Dublin. "With mild injuries they tend to have more of the emotional stuff; they tend to be more anxious. They can be fearful . . . not want to go in a car. It can also overlap with things like post-traumatic stress disorder."
People assume that because people appear to be normal, they are normal. "It's a very hidden area," says McMackin. "Often, patients are a bit better in social situations than they are at home, so there's a little of the street-angel, house-devil syndrome.
"For the spouse, the experiences are often of being entirely alone, with nobody understanding. The neighbours are saying he looks great and he's in great form, but maybe when he gets home he has a big temper outburst over the cornflakes box being upside-down."
The tension at home takes its toll. "As time goes on, the spouse gets more and more depressed, so by five years after the head injury, the spouse is suffering from a lot of stress-related illness," says McMackin.
"When you're in hospital and the person's on life support, and you're trying to get through that, you say, 'if only I had them back, that's all I ask,' but then when you're in that situation it's very different, and it gradually, very gradually, dawns on people that it's not going to go away.
"Studies show that when it is a wife who is injured, the husband tends to get much more social support. People are more willing to step into the breach if a man is left to care for a young woman."
McMackin is one of only six neuropsychologists in the Republic. "For the individuals themselves, it's a very confusing experience. If you can't really remember what life was like before, or have a good sense of what you were like before, it's hard to understand what people are talking about. They find it very distressing.
"I think that there are a lot of people with mild head injury who never get treatment and have problems, and who are wondering why they are suffering from anxiety.
"And because services are quite low, I think there are a lot of people with what we'd call moderate head injury who are let home with no obvious injuries, but they do have problems afterwards, and we don't even get to see them."
Headway Ireland offers a counselling service for people with head injuries and their families. Uain∅n Clarke of the organisation says: "it doesn't just happen to a person, it happens to a family. There is a huge cost for the carers, emotional and financial. The wear and tear is immense, and it is extremely difficult for children."
Funded through grants and donations, the organisation runs an information service and helpline. It co-ordinates a network of support groups throughout the Republic for victims and families of head-injury sufferers. It also runs vocational training courses to help people regain their independence and get back to work. Headway receives hundreds of calls each year.
Clarke adds: "A lot of people say, 'if only I had known about you seven years ago.' "
Headwayhas a helpline service at 1890-200278