We describe the 8-years follow-up of 80 patients affected by idiopathic, L-dopa-responsive Parkinson's disease. All patients were evaluated at baseline and during the follow-up with visual evoked potential, P300 event related potentials and polysomnography. The patients and their relatives compiled sleep and hallucination questionnaires. Statistical analysis was performed to evaluate if visual abnormalities, abnormal P300 recordings or sleep disturbances were linked to the development and hallucinations. Our results show that abnormal vision and abnormal P300 did not correlate with the incidence of hallucinations. However, the presence of REM sleep behavioral disorder (RBD) was significantly related to the development of hallucinations,independently of age, gender or duration of disease but dependent on the amount of dopaminoagonist treatment.
Background: Clinical studies have shown that repetitive transcranial magnetic stimulation (rTMS) is effective in a certain percentage of treatment-resistant depression (TRD). The left dorsolateral prefrontal cortex (DLPFC) 10 Hz rTMS stimulation received FDA approval in 2008, although different rTMS protocols have also shown their effectiveness in reducing depressive symptoms. We investigated the clinical, cognitive and neurophysiologic effects of a 3 weeks’ protocol of low-frequency rTMS applied over the right DLPFC in resistant depression. Methods: Twenty-eight patients with TRD (age range 28–55) received low-frequency rTMS (1 Hz) over the right DLPFC in a 3-week open trial. Hamilton scales for depression and anxiety, Corsi block-tapping test, phonemic verbal fluency, right and left resting motor thresholds were evaluated in each subject over the trial period. Results: At the end of the trial 42.9% of the subjects were considered as responders. A significant reduction of both HAMD (p < 0.001) and HAMA (p < 0.01) total scores was observed. At the 3rd week, the performances in Corsi test (p < 0.02) and phonemic verbal fluency (p = 0.065) were improved independently from depressive symptoms variation. At the end of the rTMS protocol, a significantly decreased left hemisphere resting motor threshold was registered (p < 0.01), while right hemisphere resting motor threshold did not show significant variation. Conclusion: Low-frequency rTMS over the right DLPFC appeared effective in 42.9% of depressive resistant subjects in this sample. A significant decrease in left hemisphere resting motor threshold was observed only in responders, while a trend for improvement in cognitive function has been found and appeared independent from clinical response.
Event-Related Potentials (ERPs) occurring independently from any stimulus are purely
endogenous
(
emitted potentials
) and their neural generators can be unequivocally linked with cognitive processes. In the present study, the subjects performed two similar visual counting tasks: a standard two-stimulus oddball, and an omitted-target oddball task, characterized by the physical absence of the target stimulus. Our investigation aimed at localizing the neural sources of the scalp-recorded
endogenous/emitted
ERPs. To optimize the source localization, the high temporal resolution of electrophysiology was combined with the fine spatial information provided by the simultaneous recording of functional magnetic resonance (fMRI). Both tasks identified two
endogenous
ERP components in the 300 to 520 ms interval. An earlier component, pP2, showed a bilateral generator in the anterior Insula. A later P3 component (P3b) was generated bilaterally in the temporal-parietal junction, the premotor and motor area and the anterior intraparietal sulcus (this latter one only in the standard oddball). Anticipatory slow waves (beginning 900 to 500 ms pre-stimulus), also of
endogenous
nature, were produced by the inferior and middle frontal gyrus and the supplementary and cingulate motor areas. Our protocol disentangled pre- from post-stimulus fMRI activations and provided original clues to the psychophysiological interpretation of emitted/endogenous ERPs.
Phantom limb pain is very common after limb amputation and is often difficult to treat. The motor cortex stimulation is a valid treatment for deafferentation pain that does not respond to conventional pain treatment, with relief for 50% to 70% of patients. This treatment is invasive as it uses implanted epidural electrodes. Cortical stimulation can be performed noninvasively by repetitive transcranial magnetic stimulation (rTMS). The stimulation of the hemisphere that isn't involved in phantom limb (unaffected hemisphere), remains unexplored. We report a case of phantom limb pain treated with 1 Hz rTMS stimulation over motor cortex in unaffected hemisphere. This stimulation produces a relevant clinical improvement of phantom limb pain; however, further studies are necessary to determine the efficacy of the method and the stimulation parameters.
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