Motor Control Impairments: Key Terms & Definitions

Signs

-objective findings of neuro dysfunction

Symptoms

-subjective reports

Posiitve symptoms

-release of abnormal behaviors

-ex: babinski sign

Negative symptoms

-loss of normal behaviors

-ex: paresis

Primary effects

-motor

-sensory/perceptual

-cognitive/behavioral

Secondary effects

-motor control problems

-don't result from CNS lesion directly

-are a result of a problem

Damage to motor cortex neurons or descending corticospinal pathways results in

-UMN syndrome

What happens initially after injury to motor cortex?

-spinal shock-->flaccidity

Strength

-ability to generate force

-results from musculoskeletal properties and neural activation

Neural aspects of force production

-number of motor units recruited

-type of units recruited

-discharge frequency

Paralysis (plegia)

-total loss of muscle activity

-inability to recruit high-threshold motor units

-component of UMN syndrome

paresis

-mild or partial loss of muscle activity

Muscle tone

-characterized by muscle's resistance to passive stretch

hypertonicity

-increased muscle tone

-spasticity

-rigidity

hypotonicity

-low muscle tone

spasticity

-A motor disorder characterized by velocity-dependent increased muscle tone, exaggerated tendon jerks, and clonus; the result of an upper motor neuron lesion.

-describes many abnormal behaviors

sign of spasticity

-velocity-dependent increase in resistance to passive stretch

spasticity neural mechanism

-abnormality in the segmental stretch reflex

-denervation hypersensitivity

-collateral sprouting

Individuation

-ability to selectively activate a muscle, allowing isolated joint motion

What happens when we lose individuation

-activation of one muscle is abnormally coupled with other related muscles

-decreased function

Coactivation

-simultaneous activation of muscles during functional mvmts

-present in neuro intact people just learning a skill

-also present in neuropathology

Cerebellar pathology may result in

-hypotonia

-ataxia or intention tremor

-dyssynergia (decomposition of mvmt)

-dysdiadochokinesia (inability to perform rapid alternating mvmts)

-dysarthria (deficits in articulating words)

-difficutly regulating cognition, emotion, and autonomic functions

Cerebellar discoordination manifestations

-dysmetria

-dysdiadochokinesia

-hypometria

-hypermetria

dysmetria

-inability to sustain regular rhythmic mvmts

hypometria

-underestimation of the required force or range of movement needed for specific task

-undershoot

hypermetria

-overestimation of req force or range of movement needed for specific task

-overshoot

intention tremor

-A tremor that occurs during performance of a voluntary motor act. Characteristic of cerebellar pathology.