Lee, who led Singapore from 1959 to 1990, has been diagnosed with sensory peripheral neuropathy, a disease that affects nerves outside the central nervous system and undermines balance, Lee Wei Ling wrote in her weekly column in the Straits Times.
"On some days he is fairly steady and on other days his balance is poor," said Wei Ling, who is a medical doctor and director of Singapore's National Neuroscience Institute. "Being deprived of sensation from his legs means he finds it a challenge to balance."
The 88-year-old Lee's brain and muscles are working normally, and he's walking on a treadmill three times a day to improve his balance, Wei Ling said. Lee stepped down as a cabinet minister earlier this year but is still a member of parliament and frequently travels abroad to meet foreign leaders.
