A paresis ( Greek πάρεσις páresis , German 'slack' ) is an incomplete paralysis , while complete (motor) paralysis is called paralysis or plegia . Sensitivity disorders (sensory disorders) are therefore not part of the paresis.
- In a central paresis or central paresis is 1. motoneuron (UMN) concerned extending between motor cortex / brain stem and spinal cord is located. A violation of the UMN typically leads to an impairment of the voluntary motor skills , a spastic paresis with the main symptoms of increased muscle tone ( muscle hypertension ), increased muscle reflexes , disturbed reflexes ( Babinski's sign , pyramidal sign ) and disorders of fine motor skills .
- In a peripheral paresis, however, the second motor neuron (LMN) is affected, the cell body (soma) of which is located in the anterior horn of the spinal cord , from where it sends its axon to the muscles . An injury to the LMN leads to flaccid paresis with the main symptoms of reduced muscle tone ( muscle hypotonia ), muscle atrophy , weakening or abolition of the muscle reflexes and signs of denervation ( fasciculations , fibrillation ).
Monoparesis is an incomplete paralysis of a limb or a section of a limb.
Diparesis is an incomplete paralysis of two limbs (arm and leg) or a pair of limbs (both legs or arms).
Paraparesis is the incomplete paralysis of both legs (or, in animals, the hind legs), e.g. B. as a symptom of paraplegia with residual motor skills.
Hemiparesis is the incomplete paralysis of one side of the body (unilateral or hemiplegia). If the side of the body is completely paralyzed, it is called hemiplegia . Hemiparesis is caused by a central lesion (e.g. stroke ) and typically occurs on the contralateral (opposite) side of the damage, as the affected nerve pathways cross to the opposite side and the damage site is in front of this junction (see contralaterality of the forebrain ).
Tetraparesis (also quadriparesis ) is an incomplete paralysis of all four extremities . A distinction is made between spastic and flaccid tetraparesis. With flaccid tetraparesis, the muscle tone is reduced ( hypotonic ). Spastic tetraparesis show increased ( hypertonic ) muscle tone.
Spastic tetraparesis typically results from damage to the spinal cord or from early childhood brain damage . Less common is isolated damage to the pons . Flaccid tetraparesis can z. B. arise in the context of a Guillain-Barré syndrome .
If paralysis already occurs in infancy, there is a risk that secondary, vital stimuli cannot be absorbed due to the lack of movement opportunities . Often persist characterized the infantile reflexes such as the symmetric tonic neck reflex (STNR), the tonic labyrinth reflex (TLR) or the asymmetrical tonic neck reflex (ATNR). Sufferers have problems with hand-eye coordination , bringing both hands together and crossing the middle of the body.