Final answer:
Amyotrophic Lateral Sclerosis (ALS) affects voluntary muscle control by causing the degeneration of motor neurons, leading to muscle weakness, spasticity, and eventual paralysis. The Modified Ashworth Scale measures spasticity such as Grade 3 tone in ALS patients. As the disease progresses, patients may require assistive technologies for communication and breathing.
Step-by-step explanation:
The term Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's Disease, indicates a neurodegenerative disease that primarily affects voluntary muscle control. The word 'amyotrophic' suggests a lack of muscle nourishment, leading to muscle weakness. 'Lateral' refers to the areas in the spinal cord where affected motor neurons that signal and control muscle movement are located, and 'sclerosis' implies hardening or scarring in these regions. As ALS progresses, it causes the degeneration of motor neurons, leading to a decline in voluntary muscle movement. Initially, there may be muscle tightening (or spasticity) and weakened coordination, which over time, can lead to paralysis including impairments in speech, breathing, and swallowing.
Lateral differences in muscle strength can be reflective of a deficit in one corticospinal tract versus the other. For example, a person with ALS may demonstrate Grade 3 tone in the dominant upper extremity on the Modified Ashworth Scale, which measures spasticity. The progression of ALS eventually leads to global loss of motor strength and failure of the motor system, requiring the use of assistive technologies, like brain-computer interfaces, for communication and breathing support.