Pathophysiology of somatosensory abnormalities in Parkinson disease.
Changes in sensory function that have been described in patients with Parkinson disease (PD) can be either 'pure' disorders of conscious perception such as elevations in sensory threshold, or disorders of sensorimotor integration, in which the interaction between sensory input and motor output is altered. In this article, we review the extensive evidence for disrupted tactile, nociceptive, thermal and proprioceptive sensations in PD, as well as the influences exerted on these sensations by dopaminergic therapy and deep brain stimulation. We argue that abnormal spatial and temporal processing of sensory information produces incorrect signals for the preparation and execution of voluntary movement. Sensory deficits are likely to be a consequence of the dopaminergic denervation of the basal ganglia that is the hallmark of PD. A possible mechanism to account for somatosensory deficits is one in which disease-related dopaminergic denervation leads to a loss of response specificity, resulting in transmission of noisier and less-differentiated information to cortical regions. Changes in pain perception might have a different explanation, possibly involving disease-related effects outside the basal ganglia, including involvement of peripheral pain receptors, as well as structures such as the periaqueductal grey matter and non-dopaminergic neurotransmitter systems.
Neuromed Institute IRCCS, Via Atinense 18, 86077 Pozzilli (IS), Italy.
Antonella
A
Conte
Nashaba
N
Khan
Giovanni
G
Defazio
John C
JC
Rothwell
Alfredo
A
Berardelli
D001479:Basal Ganglia / Q000503:physiopathology; D002540:Cerebral Cortex / Q000503:physiopathology; D046690:Deep Brain Stimulation; D015259:Dopamine Agents / Q000627:therapeutic use; D006801:Humans; D058748:Pain Perception / Q000502:physiology; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D010465:Perception / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D020886:Somatosensory Disorders / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D013697:Thermosensing
D015259:Dopamine Agents