Loris Karius’s calamitous performance in the Champions League final could have been a result of concussion he sustained against Real Madrid, a doctor who assessed the Liverpool goalkeeper in Boston has said.

Liverpool sent Karius for a head scan at Massachusetts General Hospital last Thursday amid concern at his reaction to a collision with Real’s captain, Sergio Ramos. The 24‑year‑old made two major errors that contributed to Real’s 3-1 victory. The first presented Karim Benzema with the opening goal and came soon after he received a blow to the head from Ramos as they challenged at the near post. Later Karius allowed Gareth Bale to put the contest beyond Liverpool with a long-range shot that squirmed through his hands.

The German flew to the US on holiday after the final but Liverpool’s medical department was sufficiently concerned about the impact of Ramos’s challenge that it arranged a scan in Boston. Karius had a consultation with Dr Ross Zafonte, an authority on head-trauma injuries suffered by NFL players and the chief of physical medicine and rehabilitation at Massachusetts General.

A statement released on Monday by the hospital on Dr Zafonte’s behalf and with the player’s permission confirmed that Karius had been concussed.

It read: “On May 31, 2018 Mr Karius underwent a comprehensive examination by Dr Ross Zafonte and Dr Lenore Herget in Boston at Massachusetts General Hospital and Spaulding Rehabilitation Hospital. After carefully reviewing game film and integrating a detailed history – including his reported present and immediate post-contact subjective symptoms – physical examination and objective metrics, we have concluded that Mr Karius sustained a concussion during the match 26 May 2018.

“At the time of our evaluation Mr Karius’s principal residual symptoms and objective signs suggested that visual spatial dysfunction existed and likely occurred immediately following the event. Additional symptomatic and objectively noted areas of dysfunction also persisted. It could be possible that such deficits would affect performance.

“We also note that Mr Karius has reported significant and steady improvement since the concussive event, and we expect him to make a full recovery based on the results of the examination. We expect that with treatment and by following prescribed activity protocols he will continue to improve. We have encouraged vigilance and an emphasis on safety in his eventual return to full activity.”

Karius has continued his holiday in California following the assessment in Boston and is due to return to pre-season training with Liverpool on 2 July.

The Anfield club have been fined €20,000 (£17,567) for disturbances at the Champions League quarter-final first leg in April, which included an attack on the Manchester City bus, Uefa announced on Monday. They were also fined €9,000 (£7,904) over the setting off of fireworks in the second leg with City and in the second leg of the semi-final at Roma.