P300 component in euthymic patients with bipolar disorder type I, bipolar disorder type II and healthy controls: a preliminary event-related potential study

The aim of the present study was to investigate P300 event-related potential components in euthymic bipolar disorder type I (BDI) and bipolar disorder type II (BDII) patients and matched controls. A total of 10 BDI patients, 10 BDII patients and 10 healthy individuals were enrolled in the study. Event-related potential data were collected according to a standard auditory 'oddball' paradigm. A significant groups effect in both the peak amplitude (P<0.001) and the mean amplitude (P<0.001) was observed; post-hoc comparisons showed that the peak and mean amplitudes of BDI and BDII patients were significantly lower than the peak and mean amplitudes of the healthy controls. The neurophysiological patterns found in the present study might at least partially reflect the presence of a mild selective cognitive impairment in euthymic BDI and BDII patients. From a clinical point of view, these evidences support the potential role of cognitive interventions in the treatment of BD

Cerebellum’s Contribution to Attention, Executive Functions and Timing: Psychophysiological Evidence from Event-Related Potentials

Since 1998, when Schmahmann first proposed the concept of the “cognitive affective syndrome” that linked cerebellar damage to cognitive and emotional impairments, a substantial body of literature has emerged. Anatomical, neurophysiological, and functional neuroimaging data suggest that the cerebellum contributes to cognitive functions through specific cerebral–cerebellar connections organized in a series of parallel loops. The aim of this paper is to review the current findings on the involvement of the cerebellum in selective cognitive functions, using a psychophysiological perspective with event-related potentials (ERPs), alone or in combination with non-invasive brain stimulation techniques. ERPs represent a very informative method of monitoring cognitive functioning online and have the potential to serve as valuable biomarkers of brain dysfunction that is undetected by other traditional clinical tools. This review will focus on the data on attention, executive functions, and time processing obtained in healthy subjects and patients with varying clinical conditions, thus confirming the role of ERPs in understanding the role of the cerebellum in cognition and exploring the potential diagnostic and therapeutic implications of ERP-based assessments in patients

Prefronto-cerebellar transcranial direct current stimulation increases amplituded and decreases latency of P3b component in patients with euthymic bipolar disorder

INTRODUCTION: Neurocognitive impairments have been observed in patients with bipolar disorder (BD) even during the euthymic phase of the disease, potentially representing trait-associated rather than state-associated characteristics of the disorder. In the present study, we used transcranial direct current stimulation (tDCS) applied to cerebellar and prefrontal cortices to improve the neurophysiological performances of patients with euthymic BD. METHODS: Twenty-five outpatients with BD underwent open-label prefrontocerebellar tDCS for 3 consecutive weeks. Neurophysiological performances were assessed through the examination of the P3b and P3a subcomponents of P300 event-related potential at baseline and after stimulation. RESULTS: Compared to baseline, P3b component after tDCS showed significantly higher amplitude and shorter latency (latency: Fz P=0.02, Cz P=0.03, and Pz P=0.04; amplitude: Fz P=0.24, Cz P=0.02, and Pz P=0.35). CONCLUSION: In our sample of patients with euthymic BD, concomitant prefrontoexcitatory and cerebellar-inhibitory modulations led to improved brain information processing stream. This improvement may at least partially result from neuroplastic modulation of prefrontocerebellar circuitry activity

Role of Functional Neuroimaging with 123I-MIBG and 123I-FP-CIT in De Novo Parkinson's Disease: A Multicenter Study

Background: Parkinson's disease is a progressive neurodegenerative disorder, with incidence and prevalence rates of 8-18 per 100,000 people per year and 0.3-1%, respectively. As parkinsonian symptoms do not appear until approximately 50-60% of the nigral DA-releasing neurons have been lost, the impact of routine structural imaging findings is minimal at early stages, making Parkinson's disease an ideal condition for the application of functional imaging techniques. The aim of this multicenter study is to assess whether 123I-FP-CIT (DAT-SPECT), 123I-MIBG (mIBG-scintigraphy) or an association of both exams presents the highest diagnostic accuracy in de novo PD patients. Methods: 288 consecutive patients with suspected diagnoses of Parkinson's disease or non- Parkinson's disease syndromes were analyzed in the present Italian multicenter retrospective study. All subjects were de novo, drug-naive patients and met the inclusion criteria of having undergone both DAT-SPECT and mIBG-scintigraphy within one month of each other. Results: The univariate analysis including age and both mIBG-SPECT and DAT-SPECT parameters showed that the only significant values for predicting Parkinson's disease in our population were eH/M, lH/M, ESS and LSS obtained from mIBG-scintigraphy (p &lt; 0.001). Conclusions: mIBG-scintigraphy shows higher diagnostic accuracy in de novo Parkinson's disease patients than DAT-SPECT, so given the superiority of the MIBG study, the combined use of both exams does not appear to be mandatory in the early phase of Parkinson's disease

Involuntary attention in essential tremor: a MMN study

Background: Essential Tremor (ET) is one of the most common neurological disorders and the most common pathologic tremor in humans. Indeed, as has been observed in several other progressive movement disorders, the motor disturbances appear to be accompanied by cognitive deficits. Aims: To investigate the involuntary attention in patients with essential tremor using the Mismatch Negativity (MMN). Methods: seventeen non-demented patients with ET and seventeen age- and sex-matched healthy controls underwent an EEG recording. MMN was evoked in a classical auditory MMN paradigm: 1000 Hz standard stimuli, occasionally interrupted by 1100HZ deviant stimuli that occurred with a probability of 0.2, were administered while subjects were watching a silent movie. ISI was set at 1 s. MMN latency and amplitude were evaluated. Results: MMN latency was prolonged in patients with elderly-onset ET (&gt;65 years) (p&lt;0.005), while no differences emerged either in latency or in amplitude between younger-onset ET and controls. Discussion: Elderly onset ET patients displayed a difficulty in the automatic involuntary processing of the stimuli, as demonstrated by the prolonged MMN latency. MMN is generated from auditory cortices bilaterally, possibly with an additional downstream component in the frontal cortex, the latter being a selective index of attentional orienting. Cerebellum, which is thought to play a major role in the pathophysiology of ET, may interfere with cognitive functioning, due to its strong and bidirectional frontal connectivity particularly to the prefrontal cortex. The differences between elderly-onset and younger-onset ET patients indicate that ET may represent a heterogeneous family of diseases united by tremor, but heterogeneous in other characteristics, as regarding cognitive functioning and in particular the automatic pre-attentive orienting. Conclusion: Our psychophysiological data shed light on the involvement of the attentional frontal network in ET, revealing a picture of the pathological process underlying this disease that is more complex than traditionally believed

Pramipexole in Parkinson's disease. A short-term study using the combined levodopa-dopamine agonist test

The aim of our study was to investigate the efficacy of pramipexole in advanced parkinsonian patients by means of an acute stimulation test. We studied the motor effects of pramipexole in fluctuating parkinsonian patients by comparing the response to acute levodopa with the response to levodopa + pramipexole. The adjunct of pramipexole to levodopa increased the time spent on from 136±22.3 to 186±20.6 minutes (p<0.01), while it did not change the latency to on, the magnitude of the motor improvement, or the duration and severity of dyskinesias. The main effect of pramipexole in fluctuating parkinsonian patients is an increased duration of the on phase