Stroke-Specific Problems Addendum slides

Weakness There was a time when spasticity/hypertonia was treated as a primary obstacle to motor function after stroke. Current evidence, however, suggests that weakness may be directly responsible for impaired motor function. Weakness includes – Impaired force magnitude – Slowness to produce force – Rapid onset of fatigue – Excessive sense of effort – Difficulty producing force effectively in the context of the task

Distribution of weakness after stroke In addition to weakness on the ipsilateral side, studies have shown varying degrees of residual strength on the more involved side. Weakness tends to be more pronounced distally than proximally. – 37% of ankle plantar flexor strength – 45% of ankle dorsiflexion – 51% of knee extension – 53% of knee flexion – 64% of hip extension – 68% of hip flexion

Impact of weakness It has NOT been shown that a direct relationship exists between strength and function, perhaps because functional movement involved simultaneous activation and coordination of multiple muscles. However, studies have shown that weakness has been associated with decreased gait performance and self-selected gait speed. The good news is that significant strength gains are attainable in acute, subacute and chronic phases of recovery!

Dealing with weakness Additional research suggests that to induce strength gains in persons after stroke, the following should be done. – Minimum intensity of 60% 1-RM (repetition maximum) and maximum of 12 repetitions/set – Three sets each of 8-10 exercises be performed 3 times/week – Even after 24 months, plateaus in strength and function are NOT likely! – Effects may be more robust in persons less affected by post-stroke hemiplegia. – Reasonable caution should be used!

Diagnosis of neglect Albert’s test is a simple test used to diagnose neglect in persons with stroke. Results were predictive of both mortality and functional activity 6 months post CVA.

Vibration therapy for neglect It is theorized that afferent sensory information (from the retina, neck muscle spindles, vestibular organs) is transformed into non-retinal spatial reference systems in a disturbed manner. The application of asymmetric vestibular stimulation, optokinetic stimulation, and neck muscle vibration, when combined, have been powerful tools to evoke transient remission of neglect symptoms.

A word on spasticity/hypertonicity Hypertonicity is considered one of the positive signs of the upper motor neuron syndrome. Some treatment approaches focus on the “normalization” of tone in order to facilitate motor recovery. A variety of treatments have been used to affect abnormal tone after stroke, including: Oral medication (Baclofen, Zanaflex) Botox Intrathecal Baclofen Nerve block

Treatments of spasticity Despite widespread use of these treatments, there is not robust support for their impact on FUNCTION!

Spasticity Research has provided insight into the pathophysiology of spasticity after stroke. In addition to cortical drive to the problem, there is an additive effect from the muscle itself. Changes in the muscle, including shortening and loss of sarcomeres, contribute to the clinical effects of spasticity. In fact, it is these changes that are more significant during gait than increased tone per se. As a result, JOINT ALIGNMENT and adequate MUSCLE LENGTH are vital pieces of the puzzle in the management of altered tone.

What does it all mean?? As a result, JOINT ALIGNMENT and adequate MUSCLE LENGTH are vital pieces of the puzzle in the management of altered tone. THE BOTTOM LINE: – Stretch – Strengthen

Recovery of global aphasia A study just published reported on the course of recovery of a patient with left hemisphere stroke over a period of 25 years! A 37-year-old man with global aphasia from ischemic lesion in left MCA was tested 9 times between 3 weeks and 25 years post stroke. The first year the patient recovery verbal comprehension and word repetition. From 1-3 years, naming and reading improved. From 3-25 years, spontaneous speech appeared.

Just a word on ataxia…… Where are we on this topic? – As recently as 1997 the prevailing theory was that the optimum way to address ataxia (result of damage to the cerebellum) was to reduce the degrees of freedom and adopting compensatory mechanisms. New understanding of neuroplasticity would suggest that the cerebellum CAN respond to rehabilitation interventions, suggesting a more restorative approach might be warranted with these patients.

What does the evidence say? A systematic review of the evidence concerning the treatment of ataxia drew several conclusions, including: – 1. There is modest evidence to support the effectiveness of PT with respect to gait, trunk control and activity limitations, but insufficient evidence to support any specific intervention. – 2. Dynamic task practice that challenges stability and explores limits of stability with little upper extremity weight bearing appear to be useful. – 3. Some patients need to be taught compensatory strategies, particularly those with severe upper limb tremor.

Gait treatments for ataxia Three studies have been done evaluating the use of locomotor treadmill training with these patients. – There appears to be encouraging evidence for the use of this treatment. Intensity and duration of the training are likely significant factors. Another useful treatment tool may be use of vision to help retrain gait. It is task specific and easy to apply in a functional setting.

A bit more on gait recovery…. The use of assistive devices, specifically those that don’t allow excessive UE weight bearing, may be useful for postural orientation and stability. However, fostering UE dependence may perpetuate gait dysfunction, or even worsen it! There is NO good evidence to support the use of axial weighting. The use of biofeedback and lycra garments is not strongly supported in the literature.

What about the arms? It has long been suggested that the use of arm weights improved limb ataxia. There are some caveats, however. – Under-weighted cuffs will not dampen tremor, while over-weighted cuffs may be no better than no weight at all. – Weighted cuffs may be too fatiguing or cumbersome to confer any benefit to the patient.

What about exercise? In general, patients with ataxia should be encouraged to exercise as a part of health promotion as long as risk factors and health and safety considerations have been assessed. No definitive answers have been found about the effectiveness of hippotherapy, hydrotherapy, Pilates, or yoga. Ataxia information summarized from : Cassidy, E et al Management of the ataxias: towards best clinical practice.