Impaired finger dexterity and nigrostriatal dopamine loss in Parkinson’s disease

Abstract

Impaired finger dexterity occurs in Parkinson's disease (PD) and has been considered a limb-kinetic apraxia associated with primary sensory cortical dysfunction. To study the role of nigrostriatal dopamine loss and elementary parkinsonian motor deficits in impaired finger dexterity of PD. Thirty-two right-handed untreated PD patients and 30 right-handed healthy controls were included. All patients underwent [F] FP-CIT positron emission tomography studies. We examined the associations among unilateral coin rotation (CR) score, Unified Parkinson's Disease Rating Scale (UPDRS) subscores for bradykinesia and rigidity of the corresponding arm, and contralateral regional striatal dopamine transporter (DAT) uptake. We also measured the effect of oral levodopa dose on CR scores and UPDRS subscores. PD patients performed worse than controls on the CR task. Unilateral arm UPDRS bradykinesia scores were associated with DAT uptake in the contralateral putamen. The left CR score was associated with left arm bradykinesia and rigidity scores and DAT uptake in the right posterior putamen, whereas no such associations were found for the right CR score. There was a significant effect of handedness on the association of putamen DAT uptake with CR scores, but not with UPDRS subscores. An oral levodopa challenge improved CR scores and UPDRS subscores on both sides. Impaired finger dexterity in PD is related to elementary parkinsonian motor deficits and nigrostriatal dopamine loss. Impaired dominant hand dexterity associated with nigrostriatal dopamine loss seems to be compensated to some extent by the dominant cerebral cortex specialized for controlling precise finger movements.

The Impact of Parkinson’s Disease on General and Specific Motor Aptitudes: A Study of Older Brazilian Adults

“…We found that most participants without PD had normal or unimpaired motor aptitude levels, while those with PD were more likely to have deficits in all areas than participants without PD, but mostly showed normal Perceptive aptitude. Although our findings were generally consistent with prior observations from other studies (Keloth et al, 2019;Lazarotto et al, 2020;Lee et al, 2018;Stegemöller et al, 2019;Stuart et al, 2019;Xu et al, 2018) our use of the MSOA permitted greater specification in describing motor aptitude differences of older adults with and without PD. Furthermore, participant gender and age group were associated with these motor aptitude outcomes, regardless of the presence or absence of PD.…”

“…Considering inherent age-related motor losses, it is important to specify the motor behavior of older adults with and without PD in order to distinguish motor deficits associated with PD (Lazarotto et al, 2020; Stuart et al, 2019). Most prior studies comparing motor skills in individuals with and without PD have evaluated gait elements (Keloth et al, 2019; Xu et al, 2018), postural control (Lazarotto et al, 2020), and manual dexterity (Lee et al, 2018; Stegemöller et al, 2019), with further research comparing multiple motor skills between these two groups limited.…”

Precisely timed dopamine signals establish distinct kinematic representations of skilled movements

“…PD patients also experience significant disability from impaired manual dexterity, which causes difficulty with tasks like tying shoelaces, fastening buttons, and handwriting (Pohar & Allyson Jones, 2009). This symptom is distinct from bradykinesia (Foki et al, 2016), but also responds to dopamine replacement (Gebhardt et al, 2008, Lee et al, 2018. Thus, dopamine plays an important, but poorly defined, role in dexterous skill beyond simply regulating movement speed or amplitude.…”

Precisely-timed dopamine signals establish distinct kinematic representations of skilled movements

“…However, PD patients also experience significant disability from impaired manual dexterity, which causes difficulty with tasks like tying shoelaces, fastening buttons, and handwriting (Pohar & Allyson Jones, 2009). This symptom is distinct from bradykinesia (Foki et al, 2016), but also responds to dopamine replacement (Gebhardt et al, 2008, Lee et al, 2018). Thus, dopamine plays an important, but poorly defined, role in dexterous skill beyond simply regulating movement speed or amplitude.…”