Initial symptoms and the rate of disease progression can vary, even from person to person within a single family. People with ALSP begin experiencing symptoms before age 60 in 95% of cases. In some rare instances, people have reported symptoms starting as young as 18 years old. Both men and women can develop ALSP, but women generally show symptoms earlier—around age 40, compared to age 47 for men.
Early symptoms of ALSP typically involve psychological and cognitive changes, but in rare cases, they can appear as motor problems, such as trouble with walking or slow movements. Seizures are reported by around 30% of people with ALSP, usually as an early symptom.
As the disease progresses, people with ALSP often experience a combination of cognitive, motor, and psychological symptoms:
- Cognitive symptoms include issues with language, memory, attention, problem solving, and impulse control, and can progress to mental decline and dementia.
- Motor symptoms include overactive reflexes, muscle stiffness, muscle spasms or tremors, weakness, slow movements, and problems with coordination, vision, and speech. These symptoms can make it difficult to walk, swallow, and speak.
- Psychological symptoms include changes in personality and mood, depression, anxiety, irritability, and issues with social behaviors.
Eventually, people with ALSP lose the ability to walk and speak, lose control of most other bodily functions, and require daily care. The average life expectancy for someone with ALSP is 8 years after symptoms begin, though actual life expectancy can range from anywhere between 2 and 30+ years depending on the individual case.