It is being widely reported that 180 Welsh and English rugby players are taking legal action against World Rugby, the Welsh Rugby Union (WRU) and the Rugby Football Union (RFU) for failing to do enough to protect players from chronic traumatic encephalopathy (CTE) which causes dementia.

CTE occurs after repeated concussive and sub-concussive blows to the head and is associated with contact sports such as rugby and American football.

A concussive blow to the head is categorised as a mild traumatic brain injury and is characterised by headache, nausea/vomiting, confusion and sometimes loss of consciousness. It results when the brain is shaken within the skull after an impact. A sub-concussive blow is one that does not reach the criteria for full concussion but nevertheless is thought to cause damage over time.

CTE varies between affected individuals but shares symptoms in common with the most prevalent type of dementia - Alzheimer's disease.

Lenny Woodard, 45, has been diagnosed with dementia which he believes was caused by playing rugby. You can read his story and hear him talk about his experiences in this BBC report - Dementia: Ex-Wales rugby star fears not recognising his children.

What is dementia?

Dementia is an umbrella term describing a set of symptoms characterised by cognitive decline over a period of time which can affect memory, problem-solving, language and behaviour.

What are the symptoms of CTE?

Typical symptoms include:

• short-term memory loss
• changes in mood
• increasing confusion and disorientation
• difficulty thinking

As CTE progresses, symptoms may develop into:

• slurred speech (dysarthria)
• significant memory problems
• parkinsonism – the typical symptoms of Parkinson's disease, including tremor, slow movement and muscle stiffness
• difficulty eating or swallowing (dysphagia)

You can read more about CTE on the NHS website here - Chronic traumatic encephalopathy.

You can read more about young-onset dementia here - Young-onset dementia | Alzheimer's Society.