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82. Prefrontal cortex as a compensatory functional substrate during ataxic overground gait: A correlation study between cortical activity and gait parameters
Society Proceedings / Clinical Neurophysiology 126 (2015) e1–e28
80. Local field potential recording abnormalities precede deep brain stimulation surgical complications in a patient with Parkinson’s disease—M. Rosa, M. Arlotti, F. Cortese, F. Cogiamanian, G. Ardolino, P. Rampini, G. Carrabba, M. Locatelli, V. Levi, A. Priori (Milano, Italy) Local field potentials (LFP) are oscillatory bioelectrical signals arising from large neuronal populations around an electrode inserted into the central nervous system. LFP recorded through deep brain stimulation (DBS) electrodes have been mainly used for experimental purposes. We report the case of a 72-year-old woman with Parkinson’s disease, who had electrodes implanted bilaterally into the subthalamic nucleus (STN) for DBS. The patient underwent bilateral STN LFP recordings two and seven days after surgery. Three days after surgery a slight weakness developed in the left limbs and a CT scan disclosed a small hemorrhagic area localized caudal to the electrode tip, in the right midbrain. Before DBS-related complications became clinically and neuroradiologically evident LFP recordings, in comparison to the contralateral side, disclosed a markedly reduced amplitude and the absence of the typical spectral peak in the right STN. This report describing STN LFP abnormalities preceding the clinical and neuroradiological evidence of a focal brain lesion suggests that recording oscillatory biopotentials through DBS electrodes could also be useful in clinical practice. This case report is unusual and novel because none have reported LFP changes associated with a brain lesion or suggesting a DBS-related complication. doi:10.1016/j.clinph.2014.10.099
81. Motor evoked potential as a predictor of clinical response in multiple sclerosis patients treated with 4 aminopyridine— M. Scarpino, G. Lanzo, A. Repice, E. Magnani, R. Carrai, A. Amantini, L. Massacesi, A. Grippo (Firenze, Italy) 4-Aminopyridine (4-AP) has been recently introduced as a symptomatic treatment of walking impairment in MS patients. The clinical benefits have been reported in about 1/3 of patients. The study was intended to verify in patients treated with 4-AP: – the ability of motor-evoked potentials (MEPs) in identifying patients responding to treatment; – if there are MEP parameters changes related to clinical improvement. Patients were enrolled in a prospective study. Patients underwent neurological examination, in order to determine: EDSS, T25WF (a walking test, measuring speed). MEPs have been recorded at lower limb, central motor conduction time (CMTT) and CMAP/ MEPs ratio have been evaluated before starting and after 30 days of 4-AP treatment. We enrolled 14 patients. Patients with high EDSS score (>4) and bilateral CMTT alteration were most likely responding to therapy. MEP parameters changes observed in some patients were not related to clinical effect measured with T25WF. The response to 4AP occurs only in 35% of MS patients. Given the drug’s side effects and its high cost, it would be useful to have predictor of response to treatment. Joining together EDSS score and CMTT value we could identify a great number of patients responding to therapy (nearly 85%). doi:10.1016/j.clinph.2014.10.100
82. Prefrontal cortex as a compensatory functional substrate during ataxic overground gait: A correlation study between cortical activity and gait parameters—P. Caliandro, M. Serrao, L. Padua, G. Silvestri, C. Iacovelli, C. Simbolotti, S. Mari, G. Reale, C. Casali, P.M. Rossini (Roma, Italy) To investigate whether prefrontal cortex (PFC) activation is linked to compensatory mechanisms (time–distance parameters) or to gait
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features (kinematic parameters) specifically related to the functional role of the cerebellum in ataxic patients. We performed a correlation analysis between the PFC metabolic profile during gait and time–distance and kinematic parameters in a sample of 19 patients affected by neurodegenerative gait ataxia and 15 age/sex matched healthy subjects. PFC metabolism was evaluated by a 2-channel functional near-infrared imaging system while gait analysis was performed using a stereophotogrammetric system. We found a positive correlation between the PFC metabolism and the step width (the correlation coefficient was r: 0.54, p = 0.02 for the right PFC, and r: 0.50, p = 0.03 for the left PFC). No correlation was found between PFC activity, the other time–distance parameters and the intra-subject variability of gait. PFC activation during ataxic gait correlates with step width and therefore it seems involved in maintaining compensatory strategies rather than due to primary cerebellar deficits. To our knowledge this is the first study correlating cortical activity and gait characteristics in order to assess how cerebral cortex is modulated during a pathological gait. doi:10.1016/j.clinph.2014.10.101
83. Skin nerve a-synuclein deposits: A biomarker for idiopathic Parkinson’s disease—V. Donadio, A. Incensi, V. Leta, M.P. Giannoccaro, C. Scaglione, S. Cappellari, P. Avoni, A. Baruzzi, R. Liguori (Bologna, Italy) (1) Whether phosphorylated a-synuclein deposits in skin nerve fibers might represent a useful biomarker for idiopathic Parkinson’s disease (IPD). (2) The underlying pathogenesis of peripheral neuropathy associated with IPD. We studied 21 well-characterized IPD patients, 20 with parkinsonisms assumed not to have a-synuclein deposits (PAR: 10 vascular parkinsonism, 6 taupathies and 4 parkin mutations) and 30 controls. Subjects underwent: nerve conduction velocities from the leg to evaluate large nerve fibers; skin biopsy from proximal (i.e. cervical) and distal (i.e. thigh and distal leg) sites to study small nerve fibers and deposits of phosphorylated a-synuclein. IPD patients showed a small nerve fiber neuropathy prevalent in the leg with preserved large nerve fibers. PAR patients showed normal large and small nerve fibers. Phosphorylated a-synuclein was not found in any skin sample in PAR patients and controls but it was found in all IPD patients in the cervical skin site. Abnormal deposits were correlated with leg epidermal denervation. Phosphorylated a-synuclein in proximal peripheral nerves is a sensitive biomarker for IPD diagnosis helping to differentiate IPD from other parkinsonisms. Neuritic inclusions of a-synuclein were correlated with a small fiber neuropathy suggesting their direct role in peripheral nerve fiber damage. doi:10.1016/j.clinph.2014.10.102
84. Functional evaluation of central cholinergic circuits in patients with Parkinson’s disease and freezing of gait— R. Dubbioso, M. Picillo, M. Amboni, R. Iodice, P. Barone, L. Santoro, F. Manganelli (Napoli, Italy, Salerno, Italy) Abnormalities of cholinergic circuitries may be at the basis of cognitive dysfunction, gait disorders, and falls and they may also be important for freezing of gait (FOG). Aim of this study is the evaluation of central cholinergic circuits by means of short latency afferent inhibition (SAI) technique in patients with Parkinson’s disease (PD) and freezing of gait (FOG+). We applied the SAI technique in 14 FOG+ patients, in 10 patients without freezing (FOG ) and in 11 age-matched normal controls. All PD patients also underwent a comprehensive battery of neuropsychological tests. Mean SAI was
80. Local field potential recording abnormalities precede deep brain stimulation surgical complications in a patient with Parkinson’s disease—M. Rosa, M. Arlotti, F. Cortese, F. Cogiamanian, G. Ardolino, P. Rampini, G. Carrabba, M. Locatelli, V. Levi, A. Priori (Milano, Italy) Local field potentials (LFP) are oscillatory bioelectrical signals arising from large neuronal populations around an electrode inserted into the central nervous system. LFP recorded through deep brain stimulation (DBS) electrodes have been mainly used for experimental purposes. We report the case of a 72-year-old woman with Parkinson’s disease, who had electrodes implanted bilaterally into the subthalamic nucleus (STN) for DBS. The patient underwent bilateral STN LFP recordings two and seven days after surgery. Three days after surgery a slight weakness developed in the left limbs and a CT scan disclosed a small hemorrhagic area localized caudal to the electrode tip, in the right midbrain. Before DBS-related complications became clinically and neuroradiologically evident LFP recordings, in comparison to the contralateral side, disclosed a markedly reduced amplitude and the absence of the typical spectral peak in the right STN. This report describing STN LFP abnormalities preceding the clinical and neuroradiological evidence of a focal brain lesion suggests that recording oscillatory biopotentials through DBS electrodes could also be useful in clinical practice. This case report is unusual and novel because none have reported LFP changes associated with a brain lesion or suggesting a DBS-related complication. doi:10.1016/j.clinph.2014.10.099
81. Motor evoked potential as a predictor of clinical response in multiple sclerosis patients treated with 4 aminopyridine— M. Scarpino, G. Lanzo, A. Repice, E. Magnani, R. Carrai, A. Amantini, L. Massacesi, A. Grippo (Firenze, Italy) 4-Aminopyridine (4-AP) has been recently introduced as a symptomatic treatment of walking impairment in MS patients. The clinical benefits have been reported in about 1/3 of patients. The study was intended to verify in patients treated with 4-AP: – the ability of motor-evoked potentials (MEPs) in identifying patients responding to treatment; – if there are MEP parameters changes related to clinical improvement. Patients were enrolled in a prospective study. Patients underwent neurological examination, in order to determine: EDSS, T25WF (a walking test, measuring speed). MEPs have been recorded at lower limb, central motor conduction time (CMTT) and CMAP/ MEPs ratio have been evaluated before starting and after 30 days of 4-AP treatment. We enrolled 14 patients. Patients with high EDSS score (>4) and bilateral CMTT alteration were most likely responding to therapy. MEP parameters changes observed in some patients were not related to clinical effect measured with T25WF. The response to 4AP occurs only in 35% of MS patients. Given the drug’s side effects and its high cost, it would be useful to have predictor of response to treatment. Joining together EDSS score and CMTT value we could identify a great number of patients responding to therapy (nearly 85%). doi:10.1016/j.clinph.2014.10.100
82. Prefrontal cortex as a compensatory functional substrate during ataxic overground gait: A correlation study between cortical activity and gait parameters—P. Caliandro, M. Serrao, L. Padua, G. Silvestri, C. Iacovelli, C. Simbolotti, S. Mari, G. Reale, C. Casali, P.M. Rossini (Roma, Italy) To investigate whether prefrontal cortex (PFC) activation is linked to compensatory mechanisms (time–distance parameters) or to gait
e19
features (kinematic parameters) specifically related to the functional role of the cerebellum in ataxic patients. We performed a correlation analysis between the PFC metabolic profile during gait and time–distance and kinematic parameters in a sample of 19 patients affected by neurodegenerative gait ataxia and 15 age/sex matched healthy subjects. PFC metabolism was evaluated by a 2-channel functional near-infrared imaging system while gait analysis was performed using a stereophotogrammetric system. We found a positive correlation between the PFC metabolism and the step width (the correlation coefficient was r: 0.54, p = 0.02 for the right PFC, and r: 0.50, p = 0.03 for the left PFC). No correlation was found between PFC activity, the other time–distance parameters and the intra-subject variability of gait. PFC activation during ataxic gait correlates with step width and therefore it seems involved in maintaining compensatory strategies rather than due to primary cerebellar deficits. To our knowledge this is the first study correlating cortical activity and gait characteristics in order to assess how cerebral cortex is modulated during a pathological gait. doi:10.1016/j.clinph.2014.10.101
83. Skin nerve a-synuclein deposits: A biomarker for idiopathic Parkinson’s disease—V. Donadio, A. Incensi, V. Leta, M.P. Giannoccaro, C. Scaglione, S. Cappellari, P. Avoni, A. Baruzzi, R. Liguori (Bologna, Italy) (1) Whether phosphorylated a-synuclein deposits in skin nerve fibers might represent a useful biomarker for idiopathic Parkinson’s disease (IPD). (2) The underlying pathogenesis of peripheral neuropathy associated with IPD. We studied 21 well-characterized IPD patients, 20 with parkinsonisms assumed not to have a-synuclein deposits (PAR: 10 vascular parkinsonism, 6 taupathies and 4 parkin mutations) and 30 controls. Subjects underwent: nerve conduction velocities from the leg to evaluate large nerve fibers; skin biopsy from proximal (i.e. cervical) and distal (i.e. thigh and distal leg) sites to study small nerve fibers and deposits of phosphorylated a-synuclein. IPD patients showed a small nerve fiber neuropathy prevalent in the leg with preserved large nerve fibers. PAR patients showed normal large and small nerve fibers. Phosphorylated a-synuclein was not found in any skin sample in PAR patients and controls but it was found in all IPD patients in the cervical skin site. Abnormal deposits were correlated with leg epidermal denervation. Phosphorylated a-synuclein in proximal peripheral nerves is a sensitive biomarker for IPD diagnosis helping to differentiate IPD from other parkinsonisms. Neuritic inclusions of a-synuclein were correlated with a small fiber neuropathy suggesting their direct role in peripheral nerve fiber damage. doi:10.1016/j.clinph.2014.10.102
84. Functional evaluation of central cholinergic circuits in patients with Parkinson’s disease and freezing of gait— R. Dubbioso, M. Picillo, M. Amboni, R. Iodice, P. Barone, L. Santoro, F. Manganelli (Napoli, Italy, Salerno, Italy) Abnormalities of cholinergic circuitries may be at the basis of cognitive dysfunction, gait disorders, and falls and they may also be important for freezing of gait (FOG). Aim of this study is the evaluation of central cholinergic circuits by means of short latency afferent inhibition (SAI) technique in patients with Parkinson’s disease (PD) and freezing of gait (FOG+). We applied the SAI technique in 14 FOG+ patients, in 10 patients without freezing (FOG ) and in 11 age-matched normal controls. All PD patients also underwent a comprehensive battery of neuropsychological tests. Mean SAI was