When motor neurons no longer stimulate muscles normally, the affected muscles may gradually shrink.
This is called **muscle atrophy**.
You might notice:
* One hand looking thinner than the other
* Reduced muscle bulk in an arm or leg
* Increasing weakness in the same area
* Clothes fitting differently because a limb has become thinner
Muscle wasting alongside weakness and twitching is one of the neurological patterns clinicians evaluate when considering ALS. ([Mayo Clinic][2])
## 9. Muscle Stiffness
ALS can also cause increased muscle tone or stiffness.
A person may feel that:
* Legs are unusually tight
* Movements are harder to initiate
* Walking feels stiff or awkward
* Muscles jerk unexpectedly
