Impact of Parkinson's disease and dopaminergic medication on proprioceptive processing

Dopaminergic contributions to distance estimation in Parkinson's disease: A sensory-perceptual deficit?

“…Instead, researchers suggest that the supplementary motor area may be involved which degrades in PD, but only responds to dopamine replacement in those with severe impairment in those regions which involve proprioceptive processing and motor execution (Jacobs & Horak, 2006;Mongeon et al, 2009). Alternatively previous studies have also suggested that dopaminergic medication worsens proprioceptive deficits in PD (Mongeon et al, 2009;O'Suilleabhain et al, 2001). The current study does not provide support for this hypothesis either, since performance 'ON' medication did not get worse during walking conditions but instead slightly improved.…”

“…First, proprioceptive processing of the upper limbs has been found to be impaired in PD (Keijsers et al, 2005;Klockgether et al, 1995;Rickards & Cody, 1997;Zia et al, 2000). When investigating PD movements (i.e., pointing or walking) in complete darkness, thus relying solely on proprioceptive information, previous studies have found reliable error in PD similar to what was seen in the current study and have concluded that these errors were a result of proprioceptive deficits (Almeida et al, 2005;Jacobs & Horak, 2006;Keijsers et al, 2005;Mongeon et al, 2009). A second possibility may be that, as has been demonstrated in previous research (Adamovich et al, 2001), visual-proprioceptive integration is impaired in PD.…”

“…During limb position tasks, individuals with PD make more errors then healthy control participants when required to identify the occurrence and/or direction of passive movements (Schneider et al, 1987) as well as demonstrating greater errors in matching static limb position, detecting limb displacements, or using the lower limbs to estimate the size of an object (Martens & Almeida, 2011;O'Suilleabhain, Bullard, & Dewey, 2001;Zia et al, 2000). Similarly, tasks involving reaching and pointing to remembered targets have found that PD patients exhibit significantly large errors when locating the original target (Keijsers, Admiraal, Cools, Bloem, & Gielen, 2005;Klockgether et al, 1995), especially when patients are unable to see their hand (Mongeon, Blanchet, & Messier, 2009) or in the complete absence of visual information (Keijsers et al, 2005). Adamovich and colleagues (2001) took these findings one step further, and showed that reaching accuracy of PD deteriorated selectively when two sources of sensory information needed to be integrated with one another (i.e., visualproprioceptive integration), which presented uncertainty as to whether spatial errors of PD arise from deficits in proprioceptive processing or from difficulty in visual-proprioceptive integration (Adamovich, Berkinblit, Hening, Sage, & Poizner, 2001).…”

“…If the BG were directly responsible for proprioceptivemotor deficits, then a homogeneous effect of dopaminergic medication would be expected since the loss of nigro-striatal dopaminergic cells ought to be robust for all PD. Instead, researchers suggest that the supplementary motor area may be involved which degrades in PD, but only responds to dopamine replacement in those with severe impairment in those regions which involve proprioceptive processing and motor execution (Jacobs & Horak, 2006;Mongeon et al, 2009). Alternatively previous studies have also suggested that dopaminergic medication worsens proprioceptive deficits in PD (Mongeon et al, 2009;O'Suilleabhain et al, 2001).…”

Dopamine Alters Tactile Perception in Parkinson's Disease

“…Despite the differential net effects of DA in M1 versus SI, it appears that the net behavioral effect is one of improvement such that movement initiation is improved and tactile performance is not degraded. However, DA medication is also shown to reduce of short latency afferent inhibition 35 , and impairs other forms of somatic sensations such as proprioception that may relate to motor symptoms 36 . L-dopa clearly improves the motor symptoms in PD but the present study demonstrates that this occurs at the expense of altering the cortico-cortical connectivity within the somatosensory system.…”