Just two months after his father gave him an e-scooter, a teenager knocked into a pedestrian, causing her to suffer severe brain injuries.

Nicholas Ting Nai Jie had failed to keep a proper lookout while riding the e-scooter on Sept 17, 2016.

Mother-of-three Ang Liu Kiow, 55, was left in a month-long coma, and her husband told The Straits Times in a subsequent interview that his homemaker wife can no longer remember the past or express herself properly.

Ting, 18, yesterday pleaded guilty to causing grievous hurt to Madam Ang while riding his e-scooter in a negligent manner.

The court heard that the 14kg device cost $1,600, and his father had bought it in July 2016.

On the day of the incident, Ting had his girlfriend with him on the e-scooter as they made their way together to Pasir Ris East Community Club. The instruction manual of his e-scooter had warned against riding with a pillion, but he ignored it.

The teenager was travelling at about 15kmh on a footpath along Pasir Ris Drive 1 when he approached a bus stop.

The court heard that he failed to keep a proper lookout and did not reduce his speed even though there were pedestrians in the vicinity.

He also did not sound the horn to inform them that he was approaching the area. When Madam Ang stepped onto the footpath in front of the bus stop, Ting applied the brakes, but it was too late.

Assistant Public Prosecutor Dillon Kok said: "The e-scooter impacted the left side of the victim, causing her to fall and hit her head on the ground. After the collision, the victim sat on the footpath and appeared dazed.

"She was helped by pedestrians to rest on the seats of the bus stop. It was observed that her eyes were open but she was not responsive. She also vomited yellowish fluid a few times."

Ting and his girlfriend remained at the scene and alerted the police. An ambulance later took Madam Ang to Changi General Hospital, where she was found to be bleeding in her brain.

The court heard that her medical, hospitalisation and therapy fees had come up to more than $107,000. After government subsidies and an insurance payout, her out-of-pocket expenses were $2,470.65 as of August last year.

On May 1 this year, new laws governing the use of personal mobility devices such as e-scooters were rolled out. As part of the Active Mobility Act, power-assisted bicycles are not allowed on footpaths, while e-scooters are banned on public roads. The speed limits are 15kmh on footpaths and 25kmh on park connectors and shared paths.

First-time offenders who flout the usage rules and speed limits may be fined up to $1,000 or jailed up to three months, or both.

Ting is expected to be sentenced today.