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Impaired control of an action after supplementary motor area lesion: A case study
No full textThe kinematics of the action formed by reaching-grasping an object and placing it on a second target was studied in a patient who suffered from an acute vascular left brain lesion, which affected the Supplementary Motor Area proper (SMA-proper) (Matelli M, Luppino G. Thalamic input to mesial and superior area 6 in the macaque monkey. Journal of Comparative Neurology 1996;372:59-87, Matelli M, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the macaque monkey. Journal of Comparative Neurology 1989;280:468-488), and in five healthy control subjects. The reach kinematics of the controls was affected by the positions of both the reaching-grasping and the placing targets (Gentilucci M, Negrotti A, Gangitano M. Planning an action. Experimental Brain Research 1997;115:116- 28). In contrast, the reach kinematics of the patient was affected only by the position of the reaching-grasping target. By comparing these results with those previously found in Parkinson's disease patients executing the same action (Gentilucci M, Negrotti A. Planning and executing an action in Parkinson's disease patients. Movement Disorders 1999;1:69-79, Gentilucci M, Negrotti A. The control of an action in Parkinson's disease. Experimental Brain Research 1999;129:269-277), we suggest that the anatomical 'motor' circuit formed by SMA-proper (see above), Basal Ganglia (BG) and Thalamus (Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends in the Neurosciences 1990;13:266-271, Hoover JE, Strick PL. Multiple output channels in the basal ganglia. Nature 1993;259:819-821) may be involved in the control of actions: SMA-proper assembles the sequence of the action, whereas BG updates its parameters and stores them. (C) 2000 Elsevier Science Ltd
Effects of disease progression and L-dopa therapy on the control of reaching-grasping in Parkinson’s disease
No full textPlanning and executing sequential motor acts in Parkinson Disease
No full textMany experimental evidences highlighted that Parkinson Disease (PD) patients are particularly impaired in performing a sequence of movements. In the present experiment we focused to study how PD patients plan and execute an action constituted by the sequence of reaching-grasping an object (first motor act) and placing it on a second target (second motor act). We wished to determine whether properties of the target of the second motor act influenced the kinematics of first motor act. The results showed that PD patients modified, as the controls, the initial ballistic phase of reaching according to variation of second target position (object extrinsic properties). In particular, peak acceleration was higher for farther position of the second target. However, in the subsequent phase the patients, differently from the controls, modified their reaching kinematics removing the effects of second target distance. In other words the patients re-programmed the reaching component by taking into account only properties of the first target. This effect was obtained by varying the duration of the acceleration phase. These results indicate that PD patients are able to compute the general program of an action that takes into account extrinsic properties of the final target. However, this program decays during its execution inducing premotor areas to reprogram it. This finding provides a further evidence of the role of the basal ganglia as structure involved in the storing motor program and in controlling the action
A study of the prevalence of restless legs syndrome in previously untreated Parkinson's disease patients: absence of co-morbid association.
No full textAbstract
OBJECTIVE: The co-morbidity between Parkinson's disease (PD) and restless legs syndrome (RLS) is currently controversial, mainly because in most of the studies so far conducted, the patients were already on therapy with dopamine(DA)ergic drugs. This study has been carried out to assess the prevalence of RLS in de novo PD patients previously unexposed to DAergic drugs.
METHODS: One hundred nine cognitively unimpaired outpatients with PD (70M/39F), mean age 66.89 years±9.37 SD were included in the study. The mean duration of PD was 15.81 months±11.24 SD, and the median Hoehn and Yahr (H&Y) stage was 2 (range 1.5-3). All patients underwent interview to assess the occurrence of overall life-time and current "primary" form of RLS according to the criteria of the International RLS Study Group (IRLSSG). One hundred sixteen age and sex matched subjects (74M/42F, mean age 66.52.years±8.65 SD) free from a history of neurological diseases, were taken as controls and likewise interviewed. "Secondary" forms of RLS in both patients and controls were subsequently excluded.
RESULTS: No significant difference was found (chi-square test) in the frequency of overall life-time and of current "primary" RLS between PD patients and controls (6 out of 109 versus 5 out of 116 and 3 out of 109 versus 3 out of 116, respectively).
CONCLUSIONS: This survey does not support the concept of a co-morbid association between the two conditions and confirm indirectly the findings of previous studies reporting the onset of RLS after diagnosis of PD has been made in the great majority of patients and so likely on ongoing DAergic treatment. Therefore, we speculate that RLS occurring in these patients could be related to DAergic therapy for PD
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