9.5 · General effects: Alterations in neuromotor function

Muscle tone

Normal state of muscle tension allowing controlled movement and maintenance of posture; controlled by the stretch reflex

Causes of altered muscle tone

Injury to any section of the motor pathway: peripheral nerve, neuromuscular junction, spinal cord, or brain

Hypertonia (rigidity)

Injury to upper motor neurons produces increased tone as the brain's inhibitory effect on spinal cord reflexes is removed

Hypotonia (flaccidity)

Injury to lower motor neurons produces decreased tone

Paresis

Weakness

Paralysis

Loss of motor neuron function so a muscle group is unable to overcome gravity

Upper motor neuron paralysis classifications

Hemiparesis/hemiplegia, paraparesis/paraplegia, and quadriparesis/quadriplegia

Hyperkinesia

Excessive movements such as tremors and tics, from physical or chemical causes such as insufficient dopamine

Disorders of posture

Inequality of tone in muscle groups from loss of normal postural reflexes

Basal ganglion posture

Stooped and hyperflexed with a narrow, short-stepped gait

Spastic gait

Shuffling gait with the leg extended and held stiff

Scissor gait

Stiff legs that swing around and cross in front

Dyspraxia/apraxia

Inability to perform tasks requiring learned motor skills; the problem is with use of muscles, not comprehension

Dysarthria

Impaired speaking

Agraphia

Impaired writing