As the disk rotates faster, the pulse frequency increases accordingly. Since the relationship between pulse frequency and rotational velocity is linear, it is a simple matter to use the pulse frequency as an indication of speed. The output pulses can be transformed into speed units by measuring their frequency, and then multiplying the frequency by an appropriate scale factor.
The life expectancy of a person with dementia is unpredictable, and the disease can progress for up to around 10 years. It is estimated that a third of people with dementia at any one time will be in the later stages of the disease.
Many older people have a slight loss of memory that does not affect their daily lives. But memory loss that gets worse may mean that you have dementia. Dementia is a loss of mental skills that affects your daily life. It can cause problems with your memory and how well you can think and plan. Usually dementia gets worse over time. How long this takes is different for each person. Some people stay the same for years. Others lose skills quickly. Your chances of having dementia rise as you get older.