Recording-2025-03-19T21:46:43.074Z

Lecture Overview

  • Focus on common diagnoses resulting from motor tract lesions in the central nervous system.

Spastic Cerebral Palsy (CP)

  • Damage to cerebrum in a developing brain.

  • Consequences of abnormal supraspinal influences leading to aberrant muscle development.

  • Movement disorders associated with spastic CP include:

    • Coordination issues.

    • Abnormal tonic stretch reflexes (both at rest and during movement).

    • Reflex radiation: reflexive activity spreads from one side of the body to the other.

    • Lack of postural preparation before movement.

  • Primary impairments:

    • Paresis of agonist postural muscles interferes with balance recovery and functional limb movements.

    • Co-contraction of muscles complicates movement.

Adult Motor Control Problems

  • Common problems arise due to motor tract damage/lesions, mainly:

    • Stroke,(CVA) - most prevalent.

    • Various spinal cord syndromes (injury, tumors).

    • ALS (Amyotrophic Lateral Sclerosis).

Stroke Focus: Middle Cerebral Artery (MCA) Stroke

  • Contralateral weakness, often more pronounced in the arm than the leg.

  • Unilateral loss of corticospinal tract integrity leads to contralateral symptoms.

  • Associated effects include:

    • Neither contraction nor hyperreflexia of elbow flexors significantly affect post-stroke upper limb activity.

  • Key impairments affecting function post-stroke:

    • Weakness and loss of fractionation (loss of isolated movements).

Myoplastic Changes Post-Stroke

  • Paretic muscles exhibit excessive resistance to stretch (hypertonia).

    • This can develop into contractures due to muscle adaptation to a shortened position.

  • EMG findings:

    • Non-paretic leg force generation correlates with EMG activity; paretic leg has high force with low EMG activity, indicating neuron damage.

  • Phasic stretch hyperreflexia seldom occurs when sufficient muscle force can be generated.

Treatment Strategies Post-Stroke

  • Effective treatments include:

    • Finger and hand movements against resistance.

    • Upper limb robotic therapy.

    • Constraint-induced movement therapy (involves constraining the non-affected limb).

    • Botox injections to combat muscle hypertonia.

    • Lower extremity interventions like stationary cycling and task-oriented gait training.

    • Treadmill training with body weight support to promote gait.

Spinal Motor Tract Lesions

  • Can be caused by various conditions, including traumatic spinal cord injuries and tumors.

  • Primary impairment is usually weakness, limiting functional activities.

  • Secondary conditions:

    • Hyperreflexia, phasic stretch reflexes, and contractures related to prolonged muscle resistance to stretch.

    • Disinhibited interneurons cause enhanced motor neuron excitability, leading to hyperreflexia.

Treatment for Spinal Cord Injury

  • Activity-based therapy stimulating the neuromuscular system below the lesion's level.

  • Treadmill training with body weight support (effective primarily in incomplete injuries).

  • Functional electrical stimulation (FES) to activate muscles through implanted or surface electrodes.

Upper and Lower Motor Neuron Signs

  • Common signs of upper motor neuron lesions:

    • Paresis, abnormal timing of muscle activation, Babinski sign, myoplastic changes from prolonged shortening.

  • Spinal cord injury signs may include:

    • Hyperreflexia, clonus, and abnormal withdrawal reflexes.

Factors Affecting Motor Function

  • Classification of motor track syndromes:

    • Cerebral motor tract syndrome (includes stroke and TBI).

    • Cerebral Palsy.

    • Spinal motor tract syndromes (including spinal cord injury and MS).

  • Myoplastic changes occur in all categories due to motor dysfunction.

Medications and Stretching

  • Medications for spasticity (baclofen, tizanidine, dantrolene) show effectiveness, mainly in MS patients.

  • Stretching may not prevent or reverse contractures in neurologic conditions due to abnormal neural input.

    • Short-term gains possible, but not permanent changes.

    • Importance of functional training over prolonged stretching emphasized.

Amyotrophic Lateral Sclerosis (ALS)

  • A degenerative disease affecting both upper and lower motor neurons, leading to:

    • Mixed symptoms (paresis, hyperreflexia, hypotonia).

  • Typically bilateral degeneration resulting in rapid progression.

  • Significant emotional impact; requires comprehensive psychosocial care.

Conclusion

  • Motor tract lesions present unique challenges in treatment and patient management.

  • Varied impairments necessitate individualized treatment focusing on function and quality of life.

Diagrammatic Summary

  • Visual representation of locations in the central nervous system affected by various motor track lesions, emphasizing differences between upper and lower motor neuron signs and conditions such as MS, stroke, CP, and spinal cord injuries.