Difference Between Hemiplegia and Hemiparesis
Hemiplegia represents complete paralysis with total loss of voluntary movement on one side of the body, while hemiparesis indicates partial weakness with preserved but diminished motor function on one side.
Core Distinction: Degree of Motor Impairment
The fundamental difference lies in the severity of motor deficit:
- Hemiplegia involves complete loss of voluntary movement with no antigravity effort or movement at all, corresponding to NIHSS motor scores of 3-4 1
- Hemiparesis denotes partial weakness of one side of the body with some preserved voluntary motor function 2
Clinical Presentation Differences
Hemiplegia Characteristics
- Presents with flaccidity in acute stages, potentially progressing to spasticity 1
- Results in severe functional limitations requiring maximal assistance for all activities of daily living 1
- Involves face, arm, and leg on one side of the body as the most frequent form of paralysis 3
- Causes muscular wasting on the affected side, impairs gait, reduces motor abilities, and causes instability and loss of grasping capacity 4
Hemiparesis Characteristics
- Demonstrates potential for functional ambulation, though energy expenditure may be elevated up to 2 times that of able-bodied persons 1
- Patients have variable independence in activities of daily living depending on severity 1
- Allows for some voluntary movement, though patients with movement in the hemiparetic shoulder have higher rates of shoulder joint tissue injury on MRI, suggesting more physical activity promotes injury 1
Functional and Prognostic Implications
Energy Expenditure and Mobility
- Energy expenditure during gait varies with the degree of weakness, spasticity, training, and bracing 1
- Hemiplegic patients demonstrate markedly elevated oxygen cost of walking compared to able-bodied subjects, with mechanical efficiency reduced up to 50% 1
Long-term Outcomes
- Between 25% and 50% of stroke survivors require at least some assistance with activities of daily living, with half experiencing severe long-term effects such as partial paralysis (hemiparesis) or complete paralysis (hemiplegia) 1
Distinguishing Features in Clinical Assessment
Key assessment point: Limb apraxia is defined as "a decrease or difficulty in performing purposeful, skilled movements" that cannot be attributed to hemiplegia or lack of effort, emphasizing that hemiplegia itself precludes voluntary skilled movement 5
Common Pitfalls to Avoid
- Do not confuse hemiplegia/hemiparesis with hemispatial neglect, which is a neuropsychological condition involving deficit in attention and awareness of one side of space, not attributable to primary motor deficit 5
- Strictly unilateral lesions at C1-T2 result in clinical involvement on only the affected side of the body (hemiparesis or hemiplegia), while lesions at different spinal levels produce different patterns 6