Question

An impairment in the ability to make voluntary movements in the absence of paralysis or a muscle disorder is known as:

Answer 1

UMN lesions impair voluntary movements without paralysis or direct muscle disorders, often retaining muscle tone and showing spasticity, unlike LMN lesions which cause flaccid paralysis.

Step-by-step explanation:

An impairment in the ability to make voluntary movements in the absence of paralysis or a muscle disorder is known as an upper motor neuron (UMN) lesion. UMN lesions are characterized by a loss of voluntary control over movements while muscle tone is retained and spasticity may be present. This is in contrast to a lower motor neuron (LMN) lesion, which leads to flaccid paralysis, accompanied by a loss of muscle tone and reflexes, and can involve symptoms like muscle weakness, fibrillation, and fasciculations. In diseases such as amyotrophic lateral sclerosis (ALS), motor neuron degeneration progresses from muscle weakness and lack of coordination to eventual paralysis.