Types of Stroke That Cause Finger Extensions
Strokes affecting the primary motor cortex or corticospinal tract that spare finger extensor pathways can result in preserved or enhanced finger extension movements.
Stroke Location and Finger Extension
- Lacunar infarcts in subcortical areas are most commonly associated with preserved finger extension, as they typically affect small vessels deep in the brain or brain stem rather than cortical motor areas 1
- Constraint-induced movement therapy guidelines specifically identify patients with at least 10 degrees of finger extension as candidates for this therapy, indicating that some stroke patients retain this ability 2
- The National Institutes of Health Stroke Scale (NIHSS) often includes an additional assessment item for finger extension, highlighting its clinical significance in stroke evaluation 2
Neuroanatomical Considerations
- Motor somatotopy (the organization of motor control areas in the brain) is generally preserved after injury to primary sensorimotor cortex, which can explain retained finger extension abilities 3
- In some stroke patients, the region of motor cortex activated during ipsilateral hand movements is spatially distinct from that identified during contralateral hand movements, which may contribute to preserved finger extension 4
- Surviving regions of motor cortex can actively participate in movement control processes despite stroke producing contralateral hemiplegia 5
Clinical Implications
- Patients with at least 20 degrees of wrist extension and 10 degrees of finger extension are specifically identified as candidates for constraint-induced movement therapy 2
- The presence of voluntary finger extension is considered a positive prognostic indicator for upper extremity motor recovery 2
- Finger extension is considered so important that it is often added as an additional assessment item to the NIHSS, even though it doesn't contribute to the total score 2
Rehabilitation Considerations
- Task-specific practice focusing on wrist and finger extension movements should be implemented as a core rehabilitation strategy for patients who demonstrate this ability 6
- For patients with some voluntary finger extension, constraint-induced movement therapy is recommended to improve upper extremity motor coordination 2
- Functional electrical stimulation may be considered as an adjunctive therapy to improve motor control in patients with limited finger extension 2
Cautions and Limitations
- Avoid prolonged positioning of the wrist at end ranges, as this may exacerbate symptoms in patients with preserved finger extension 6
- The use of splints and taping are not recommended for prevention of wrist and finger spasticity after stroke 2
- While some stroke patients retain finger extension ability, many develop joint contractures on the affected side within the first year, with wrist contractures occurring most commonly in patients who do not recover functional hand use 2
Remember that the presence of finger extension after stroke is a positive prognostic sign and should guide rehabilitation approaches, particularly regarding the appropriateness of constraint-induced movement therapy and other targeted interventions.