@article{IsaiasVolkmannMarzeganetal.2012,
  author    = {Isaias, Ioannis U. and Volkmann, Jens and Marzegan, Alberto and Marotta, Giorgio and Cavallari, Paolo and Pezzoli, Gianni},
  title     = {The Influence of Dopaminergic Striatal Innervation on Upper Limb Locomotor Synergies},
  series = {PLoS One},
  volume    = {7},
  journal   = {PLoS One},
  number    = {12},
  doi       = {10.1371/journal.pone.0051464},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133976},
  pages     = {e51464},
  year      = {2012},
  abstract  = {To determine the role of striatal dopaminergic innervation on upper limb synergies during walking, we measured arm kinematics in 13 subjects with Parkinson disease. Patients were recruited according to several inclusion criteria to represent the best possible in vivo model of dopaminergic denervation. Of relevance, we included only subjects with normal spatio-temporal parameters of the stride and gait speed to avoid an impairment of upper limbs locomotor synergies as a consequence of gait impairment per se. Dopaminergic innervation of the striatum was measured by FP-CIT and SPECT. All patients showed a reduction of gait-associated arms movement. No linear correlation was found between arm ROM reduction and contralateral dopaminergic putaminal innervation loss. Still, a partition analysis revealed a 80\% chance of reduced arm ROM when putaminal dopamine content loss was >47\%. A significant correlation was described between the asymmetry indices of the swinging of the two arms and dopaminergic striatal innervation. When arm ROM was reduced, we found a positive correlation between upper-lower limb phase shift modulation ( at different gait velocities) and striatal dopaminergic innervation. These findings are preliminary evidence that dopaminergic striatal tone plays a modulatory role in upper-limb locomotor synergies and upper-lower limb coupling while walking at different velocities.},
  language  = {en}
}
@article{IsaiasMarzeganPezzolietal.2012,
  author    = {Isaias, Ioannis U. and Marzegan, Alberto and Pezzoli, Gianni and Marotta, Giorgio and Canesi, Margherita and Biella, Gabriele E. M. and Volkmann, Jens and Cavallari, Paolo},
  title     = {A role for locus coeruleus in Parkinson tremor},
  series = {Frontiers in Human Neuroscience},
  volume    = {5},
  journal   = {Frontiers in Human Neuroscience},
  number    = {179},
  doi       = {10.3389/fnhum.2011.00179},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133955},
  year      = {2012},
  abstract  = {We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease(PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [\(^{123}\)I] N-\(\omega\)-fluoropropyl-2 \(\beta\)-carbomethoxy-3 \(\beta\)-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor.},
  language  = {en}
}
@article{IsaiasDipaolaMichietal.2014,
  author    = {Isaias, Ioannis Ugo and Dipaola, Mariangela and Michi, Marlies and Marzegan, Alberto and Volkmann, Jens and Rodocanachi Roidi, Mariana L. and Frigo, Carlo Albino and Cavallari, Paolo},
  title     = {Gait Initiation in Children with Rett Syndrome},
  series = {PLoS ONE},
  volume    = {9},
  journal   = {PLoS ONE},
  number    = {4},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0092736},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119789},
  pages     = {e92736},
  year      = {2014},
  abstract  = {Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait.},
  language  = {en}
}