Cerebral palsy
Direct physical trauma to the affected limb
Central nervous mass lesion, including tumor, hematoma, or abscess
Complicated migraine
Epilepsy
Head or spinal trauma
Hereditary brachial neuritis
Hereditary neuropathy with liability to pressure palsy
Neonatal brachial plexus paralysis
Neuropathy
Plexopathy
Traumatic peroneal neuropathy
Vaccine-associated paralytic poliomyelitis
Hemiparetic seizures
Monomeric spinal muscular atrophy
StrokeSpecifically, monoplegia in the lower extremities is typically caused by Brown Sequard syndrome and hematomas in the frontoparietal cortex near the middle that could produce a deficit such as this, but this is a very uncommon occurrence. Mechanism
In monoplegia, the spine and the proximal portion of nerves are usually the abnormal sites of limb weakness. Monoplegia resulting from upper extremity impairments following a stroke occurs due to direct damage to the primary motor cortex, primary somatosensory cortex, secondary sensorimotor cortex, sensorimotor cortical areas, subcortical structures, and/or the corticospinal tract. It is often found that impairments following stroke are either caused by damage to the same or adjacent neurological structures. A combination of these impairments is more likely than just one in isolation. Damage to the corticospinal system results in an inability to activate muscles with enough force or in a coordinated manner, which can lead to paresis, loss of fractional movement, and abnormal muscle tone. Damage to the somatosensory cortical areas causes loss of somatosensation which results in an impaired ability to monitor movement.Considering monoplegia as it relates to cerebral palsy, in premature infants, the most common cause of cerebral palsy is periventricular hemorrhagic infarction. In term infants, the underlying causes are often cerebral malformations, cerebral infarction, and intracerebral hemorrhage.
More research needs to be conducted in order to establish the lasting benefit of constraint-induced movement therapy. Brain computer interface (BCI) systems have been proposed as a tool for rehabilitation of monoplegia, specifically in the upper limb after a stroke. BCI systems provide sensory feedback in the brain via functional electrical stimulation, virtual reality environments, or robotic systems, which allows for the use of brain signals. This is extremely crucial because the networking in the brain is often compromised after a stroke, leading to impaired movement or paralysis. BCI systems allow for detection of intention to move through the primary motor cortex, then provide the matched sensory stimulation according to feedback that is provided. This leads to activity-dependent plasticity within the user, requiring them to pay careful attention to tasks that require the activation or deactivation of specific brain areas. BCI systems utilize different sources of information for feedback, including electroencephalography (EEG), magnetoencephalography, functional magnetic resonance imaging, near-infrared spectroscopy, or electrocorticography. Among all of these, the EEG signals are the most useful for this type of rehabilitation because they are highly accurate and stable.Another form of treatment for monoplegia is functional electrical stimulation (FES). It is targeted at patients who acquired monoplegia through incidents such as a spinal cord injury, stroke, multiple sclerosis, or cerebral palsy and utilizes electrical stimulation in order to cause the remaining motor units in the paralyzed muscles to contract. As in traditional muscular training, FES improves the force with which the unaffected muscles contract.