80 Hz versus 130 Hz subthalamic nucleus deep brain stimulation: Effects on involuntary movements

BackgroundSubthalamic Nucleus Deep Brain Stimulation (STN-DBS) represents a valid therapeutic option for advanced Parkinson's disease (PD), leading to a significant amelioration of motor fluctuations and levodopa-induced involuntary movements (IM). This study address the issue of whether stimulation frequency may influence the control of IM in STN-DBS treated patients, comparing the effects of 80 Hz and 130 Hz STN-DBS frequencies in 10 parkinsonian patients with residual IM (dyskinesia in 6 cases and dystonia in 4 cases).MethodsPatients were evaluated by means of the Rush Dyskinesias Rating Scale (blinded-video analysis) and Unified Parkinson's Disease Rating Scale at 4 different time-points: baseline, shortly after the switch of stimulation frequency from 130 Hz to 80 Hz, after 1 month and 12 months of chronic 80 Hz stimulation.ResultsIM improved in most subjects after the switch of stimulation frequency: dyskinesias improved in 6/6 subjects and dystonic features in 3/4 subjects after one month of 80 Hz stimulation. However, the 130 Hz STN stimulation was restored in 4 subjects during the following months, because of a gradual worsening of parkinsonian symptoms. A sustained efficacy on motor features and IM was observed with 80 Hz stimulation frequency in the remaining patients.ConclusionsIn this limited cohort of STN-DBS patients, we observed an improvement of residual IM after the switch of stimulation frequency from 130 Hz to 80 Hz. However, a moderate worsening of parkinsonian symptoms was observed in a portion of patients, requiring to return at 130 Hz STN-DBS.     

Effect of interstimulus interval on visual P300 in Parkinson's disease

OBJECTIVE: Visual event related potentials (ERPs) were studied during an oddball paradigm, to testify whether cognitive slowing in Parkinson's disease exists and to investigate whether cognitive information processing can be influenced by different interstimulus intervals (ISIs) of an oddball task in patients with Parkinson's disease and normal subjects. METHODS: ERPs and reaction time were measured in 38 non-demented patients with Parkinson's disease and 24 healthy elderly subjects. A visual oddball paradigm was employed to evoke ERPs, at three different interstimulus (ISI) intervals: ISI(S), 1600 ms; ISI(M), 3100 ms; and ISI(L), 5100 ms. The effect of ISIs on ERPs and reaction time was investigated. RESULTS: Compared with the normal subjects, P300 latency at Cz and Pz was significantly delayed after rare target stimuli in patients with Parkinson's disease only at ISI(L). Reaction time was prolonged in patients at all the three ISIs, compared with the normal controls. There was also significantly delayed N200 and reduced P300 amplitude at Cz and/or Pz to rare non-target stimuli in patients at the three ISIs, compared with the normal controls. During rare target visual stimulation, P300 latency and reaction time in the patients with Parkinson's disease and reaction time in the normal subjects were gradually prolonged as the ISI increased. CONCLUSION: Prolonged N200 latency to rare non-target stimuli might indicate that automatic cognitive processing was slowed in Parkinson's disease. Cognitive processing reflected by P300 latency to rare target stimuli was influenced by longer ISI in patients with Parkinson's disease.     

Subthalamic stimulation and levodopa modulate cortical reactivity in Parkinson's patients

BackgroundThe effects of deep brain stimulation of the subthalamic nucleus (DBS-STN) and L-dopa (LD) on cortical activity in Parkinson's disease (PD) are poorly understood.ObjectivesBy combining transcranial magnetic stimulation (TMS) and electroencephalography (EEG) we explored the effects of STN-DBS, either alone or in combination with L-Dopa (LD), on TMS-evoked cortical activity in a sample of implanted PD patients.MethodsPD patients were tested in three clinical conditions: i) LD therapy with STN-DBS turned on (ON/ON condition); ii) without LD therapy with STN-DBS turned on (OFF/ON condition); iii) without LD therapy with STN-DBS turned off (OFF/OFF condition). TMS pulses were delivered over left M1 while simultaneously acquiring EEG. Eight age-matched healthy volunteers (HC) were tested as a control group.ResultsSTN-DBS enhanced early global TMS-evoked activity (∼45–80ms) and high-alpha TMS-evoked oscillations (11–13 Hz) as compared to OFF/OFF condition, independently from concomitant LD therapy. LD intake (ON/ON condition) produced a further increase of late TMS-evoked activity (∼80–130ms) and beta TMS-evoked oscillations (13–30 Hz), as compared to OFF/OFF and OFF/ON conditions, that normalized reactivity as compared to HC range of values.ConclusionsOur data reveal that bilateral STN-DBS and LD therapy induce a modulation of specific cortical components and specific ranges of frequency. These findings demonstrate that STN-DBS and LD therapy may have synergistic effects on motor cortical activity.     

Decreasing subthalamic deep brain stimulation frequency reverses cognitive interference during gait initiation in Parkinson’s disease

Objective

Freezing of gait (FOG) represents a major burden for Parkinson’s disease (PD) patients. High-frequency (130-Hz) subthalamic deep-brain-stimulation (STN-DBS) has been reported to aggravate FOG whereas lowering the frequency to 60–80?Hz improves FOG. To further understand the effects of STN-DBS on FOG, we assessed the effects of 80-Hz and 130-Hz STN-DBS on gait initiation performance, in relation to motor and executive function processing.

Effect of acute deep brain stimulation of the subthalamic nucleus on auditory event-related potentials in Parkinson's disease

ObjectiveThe analysis of long-latency event-related potentials (ERPs) is an important approach in the evaluation of certain cognitive functions, particularly selective attention, and in following their subsequent changes. Auditory P300 has previously been reported to be abnormal in patients with Parkinson's disease (PD). The aim of this study was to investigate whether acute deep brain stimulation (DBS) of the subthalamic nucleus (STN) itself can cause changes in the configuration of ERPs.MethodUsing a standard auditory oddball paradigm, we elicited ERPs in 10 patients with PD (in both DBS-ON and DBS-OFF conditions). The patients acted as their own controls. The N100, P200, N200 and P300 latencies, amplitudes and areas were compared between DBS-ON and DBS-OFF states. The motor reaction times were also recorded and compared between the two states.ResultsComparison of the DBS-ON and DBS-OFF states revealed that neither amplitudes nor areas of the ERP components changed significantly; however, significant changes were observed in the latency of N100 potential when the target stimulus was applied, although there was no significant change in the latency of the P300 potential. No significant changes were noted in the latencies of the other observed ERP components. There was a marked improvement in the reaction time after the DBS electrode was turned ON.ConclusionOur data indicate that DBS might have varied impacts on electrophysiological parameters during the auditory oddball paradigm. Moreover, it may also worsen the orientation response as reflected by the increase in the N100 latency after the DBS electrode is turned ON.     

Contribution of auditory P300 test to the diagnosis of mild cognitive impairment in Parkinson’s disease

Abnormalities in auditory P300 test have been observed in patients with Parkinson’s disease (PD). We aimed to investigate whether or not additional electrophysiological tests assist in making the clinical diagnosis of mild cognitive impairment in Parkinson’s disease (PD-MCI), and we evaluated P300 changes in patients with non-demented PD and analyzed the correlation between the cognitive features and P300 changes. Twenty patients with PD who had been diagnosed with mild cognitive impairment (PD-MCI group) according to the Movement Disorder Society (MDS) 2012 PD-MCI level II criteria, 21 patients with PD without cognitive impairment (PD-Normal group), and 20 control subjects (control group) who were neurologically normal were examined by the standard auditory oddball paradigm. The N100, P200, N200, and P300 latencies and N100-P200, P200-N200, and N200-P300 amplitudes were measured and analyzed. P300 latencies recorded from Fz, Cz, and Pz and N200 latency recorded from Fz were significantly longer in the PD-MCI group than in the PD-Normal and the control group (respectively p < 0.001, p = 0.041). P300 amplitude recorded from Fz was significantly lower in PD-MCI group than those in the other groups (p = 0.038). While P300 was obtained in all patients in the PD-Normal and the control group, it was lost in 35% of PD-MCI patients. The results show that P300 provides a diagnostic tool for detecting PDMCI. We suggest that P300 prolongation and loss of P300 potential could be used as supportive parameter in the diagnosis of PD-MCI.     

Lower P300 amplitude in eight-year-old offspring of alcoholic fathers with a delinquent history

The aim of the present study was to investigate the P300 amplitude as a possible vulnerability marker in children of alcoholic (COA) fathers with and without paternal delinquency. Event-related potentials (ERPs) of 122 children aged 8 years (63 boys, 59 girls) were compared depending on father’s alcoholism subtype: 30 COAs without paternal delinquency, 10 COAs with paternal delinquency, and 82 children of non-alcoholic and non-delinquent fathers. ERPs were recorded from Fz, Cz, and Pz, using an auditory oddball paradigm. Sinus tones of 60 dB HL were presented binaurally at 1,000 Hz (standard stimulus) and 2,000 Hz (target stimulus), at a relative frequency ratio of 80:20. Two trial blocks of 250 stimuli each were collected. Results indicated that only COAs with paternal delinquency displayed significant differences from the control group, characterized by reduced P300 amplitude at frontal site and in the second trial block. Thus, the combination of fathers’ alcoholism and delinquency was more likely to relate to attenuated P300 amplitude in the offspring than paternal alcoholism alone. Our results suggest that both alcoholic and delinquent family history appear to play a role in P300 amplitude reduction in the offspring.     

Early sensory information processes are enhanced on visual oddball and S1-S2 tasks in Parkinson's disease: a visual event-related potentials study

To observe sensory and cognitive information processing in Parkinson's disease (PD), 34 PD patients and 26 controls were investigated. A visual oddball paradigm and an S1–S2 paradigm were employed to record the early (P1, N1, P2) and late (N2, P3) event-related potentials (ERPs) at Cz, Pz and Oz. Results showed: (1) enlarged P1 amplitude at all electrode locations on both tasks, (2) shortened N1 latency and enlarged P2 amplitude at Oz on both tasks, (3) enlarged N1 amplitude at Cz during an oddball paradigm, (4) delayed N2 latency and decreased N2, P3 amplitude on both tasks, and (5) delayed P3 latency and reaction time during the S1–S2 paradigm. Abnormal ERP changes were correlated with worsened scores on Wechsler Adult Intelligence Scale-Revised and motor dysfunction scales in PD. We surmise overactive aspects or failed inhibitory modulation of sensory information processing in the early ERP stage and deficient cognitive information processing during the late ERP stage in PD.     

Auditory event-related potentials in panic disorder

To investigate the psychophysiological features of panic disorder (PD), we recorded auditory event-related potentials (ERPs) in 12 patients with PD meeting the DSM-IV criteria and in 12 age-matched normal controls. The ERPs were recorded during a standard two-tone discrimination task (oddball task). The probabilities of the rare target (1200 Hz) and frequent non-target tones (1000 Hz) were 15 and 85%, respectively. The subjects were required to press a button in response to the rare target tones. Scalp electroencephalograms were recorded from Fz, Cz, Pz, C3, and C4. The State-Trait Anxiety Inventory and Manifest Anxiety Scale scores were assessed for clinical evaluation. Analysis of variance revealed that the N1 and N2 amplitudes for target tones and the N1 amplitude for non-target tones were significantly larger in the PD patients than those in the controls. The two groups did not differ significantly in P3 latency and amplitude. The larger N1 and N2 amplitudes in the PD patients are suggestive of alteration of early information processing in PD.     

Does subthalamic nucleus deep brain stimulation affect the static balance at different frequencies?

PurposeTo investigate the effects of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) with different stimulation frequencies on static balance.Materials and methodsTwenty patients (15 males and 5 females), aged between 43 and 81 (mean: 60.05 ± 7.4) years, who had been diagnosed with idiopathic Parkinson's disease (PD) and undergone STN-DBS surgery were included in the study. Static balance was assessed with TecnoBody Rehabilitation System at four different frequencies: 230, 130, 90 and 60 Hz and off-stimulation. Static balance tests were ‘stabilometric test, stabilometric compared bipedal closed/opened eye, stabilometric compared mono pedal (right/left foot)’. These tests reported the centre of pressure data ‘ellipse area, perimeter, front/back and mediolateral standard deviations’.ResultsThere were no statically differences between the static balance test results at any frequency (p > 0.05), but results were found better at 90 Hz. Stabilometric compared bipedal opened eye forward–backward standard deviation result was significant between off-stimulation and 130 Hz (p = 0.04). Different frequency stimulation affected the static balance categories percentage with no statistical significance between off-stimulation and others (all p > 0.05).ConclusionThis study showed that STN-DBS did not affect the static balance negatively. Low-frequency (LF) stimulation improved the static equilibrium. Posturography systems will give more precise and quantitative results in similar studies with wide frequency ranges.     

Pure word deafness due to left subcortical lesion: Neurophysiological studies of two patients

ObjectiveThis study investigated the auditory processing in two patients with pure word deafness (PWD) using neurophysiological experimental methods.MethodsWe recorded the auditory brainstem response (ABR), the middle latency auditory-evoked response (MLR) and the auditory-evoked event-related potentials (ERPs) in two patients with PWD after subcortical hemorrhage in the left temporal lobe.ResultsBoth patients showed normal response in ABR and abnormality in MLR. The latency of P300 evoked by right-ear stimulation was 51 ms longer in one patient and 26 ms longer in the other patient than that evoked by left-ear stimulation.ConclusionsOur results suggested that the prolongation of P300 latency could be caused by the deterioration of auditory stimulus processing and supported the hypothesis that the defect in auditory temporal resolution was an important factor in the development of PWD.SignificanceThis study demonstrated that recordings of ERP with auditory-evoked response such as ABR and MLR are useful to elucidate the deterioration of auditory stimulus processing in patients with PWD.     

The mismatch negativity and the P3a components of the auditory event-related potentials in autistic low-functioning subjects.

OBJECTIVE: In order to understand better the psychophysiological basis of auditory processing abnormalities in autism, we decided to study two automatic components of the auditory event-related potentials (ERPs): the mismatch negativity (MMN)--a component of the ERP which is recorded when, during repetitive auditory stimulation, rare changes are introduced--and the novelty-related P3a which is recorded as a response to unexpected novel events occurring in a sequence of repetitive stimuli. METHODS: Ten male subjects, mean age 12.3 years (SD 4.95), affected by autism and mental retardation were admitted to this study. All patients were also mentally retarded. Ten normal male subjects, mean age 12.2 years (SD 3.94), were used as controls. Auditory evoked potentials were recorded from 19 scalp electrodes (10-20 system), and stimuli were presented in sequences consisting of 2000 tones (70 dB, ISI=800 ms). Three types of stimuli were presented: (1) standard stimuli (1000 Hz tones, 80% of total stimuli), (2) deviant stimuli (1300 Hz tones, 10% of total stimuli), and (3) novel stimuli (complex and non-monotonal, 10% of total stimuli). To quantify the MMN, the evoked response to the standard tones was subtracted from the corresponding deviant stimulus response and its amplitude and latency at peak were measured over Fz, Cz and Pz; similarly, the P3a component of the ERP was obtained by subtracting the response to the standard tone from that to the novel stimuli and its amplitude and latency at peak were measured over Fz, Cz and Pz. Also, the amplitude and latency at peak for the N1 component of the auditory evoked potential obtained with the standard stimuli were measured over Fz, Cz and Pz. The correlation between age and MMN and P3a amplitude was also analyzed. RESULTS: N1 showed significantly shorter latencies in the autistic groups. MMN elicited by deviant stimuli, but not that elicited by novel stimuli, was found to be significantly larger in autistic children than in normal controls. P3a showed higher amplitude in autistic subjects than in normal controls during childhood; the opposite was observed during young adulthood. DISCUSSION: Our findings indicate that significant changes in ERPs can also be seen in non-cooperative individuals with autism and mental retardation, which might be different from the changes already reported for high-functioning autistic subjects and deserve further insight. These changes show developmental modifications that should be taken into consideration when analyzing data from autistic subjects.     

Deep brain stimulation fine-tuning in Parkinson's disease: Short pulse width effect on speech

Backgroundsubthalamic nucleus deep brain stimulation (STN-DBS) may have a detrimental effect on speech in Parkinson's disease (PD) patients and new stimulation technologies may help in addressing this issue.Objectiveto evaluate the STN-DBS acute effect of 30 μs pulse width (30PW) versus conventional 60 μs PW (60PW) on speech and identify the core features of voice modified by 30PW.Methodsseven STN-DBS treated PD patients participated into a pilot cross-sectional study. Motor and speech performances were tested by means of both automatic analysis and blinded clinical evaluations in four stimulation conditions: 30PW and 60PW both at the usual amplitude and at an amplitude just below the threshold for stimulation-related side effects.Resultsat the threshold amplitude, 30PW stimulation improved speech intelligibility for both words (p = 0.02) and sentences (p = 0.04), without worsening motor performance. A lower but not statistically significant voice variability and instability and percentage of stuttering disfluencies was also observed. The beneficial effect of 30PW detected by automatic analysis, was confirmed by patients’ perception.ConclusionsSTN-DBS treated patients experiencing low speech intelligibility may benefit from a 30PW stimulation trial at a higher amplitude. Deep characterization of PD speech profiles may help in a better application of recent DBS hardware advances.     

Event-related potentials to emotional and neutral stimuli

Abstract

The present study examined subjects' cognitive processing of pictures of emotional and neutral facial expressions, as measured by Event-Related Potentials (ERPs). In Experiment 1, 10 subjects viewed two slides of a woman modelling angry and happy expressions; in Experiment 2, 10 subjects viewed slides of two women modelling neutral expressions. One face appeared on 20% of the trials and the other on 80% of the trials. Subjects counted the low frequency target face. In both experiments, the area of the P300 component was larger at Pz than Cz. In Experiment 1, P300 area was larger when the target was happy; peak amplitude was greater when the target was angry. No differences between neutral target faces were found for P300 amplitude or area in Experiment 2. These results suggest that emotional versus neutral facial expressions elicit different electrophysiological responses; responses are further differentiated to positive versus negative expressions.     

不同症状的精神分裂症患者事件相关电位研究

目的研究以不同症状为主的精神分裂症患者的事件相关电位。方法对16例阴性症状为主、19例阳性症状为主、21例混合型未服药的精神分裂症患者和15例正常对照组，进行ERPsN200、P300测查。结果三组精神分裂症患者中P300波幅与正常对照组相比均明显下降，差畀具有显著性（P〈0．05），只有阴性组P300的潜伏期与正常对照组相比明显延长（P〈0．05）；三组精神分裂症患者中T3点P300波幅与T4相比下降更明显（P〈0．05）；相关分析发现，阴性量表分与Fz的P300潜伏期显著正相关（r=0．33，P〈0．05）。结论不同症状为主的精神分裂症可能有不同的神经生物学基础。     

CHANGES IN P300 FOLLOWING TWO YOGA-BASED RELAXATION TECHNIQUES

Cyclic meditation (CM) is a technique that combines “stimulating” and “calming” practices, based on a statement in ancient yoga texts suggesting that such a combination may be especially helpful to reach a state of mental equilibrium. The changes in the peak latency and peak amplitude of P300 auditory event–related potentials were studied before and after the practice of cyclic meditation compared to an equal duration of supine rest in 42 volunteers (group mean age ± SD, 27 ± 6.3 years), from Fz, Cz, and Pz electrode sites referenced to linked earlobes. The sessions were one day apart and the order was alternated. There was reduction in the peak latencies of P300 after cyclic meditation at Fz, Cz, and Pz compared to the “pre” values. A similar trend of reduction in P300 peak latencies at Fz, Cz, and Pz was also observed after supine rest, compared to the respective “pre” values, although the magnitude of change in each case was less after supine rest compared to after cyclic meditation. The P300 peak amplitudes after CM were higher at Fz, Cz, and Pz sites compared to the “pre” values. In contrast, no significant changes were observed in the P300 peak amplitudes at Fz, Cz, and Pz after supine rest compared to the respective “pre” state. The present results support the idea that “cyclic” meditation enhances cognitive processes underlying the generation of the P300.     

草酸艾司西酞普兰对抑郁症患者事件相关电位P300的影响

目的:探讨草酸艾司西酞普兰对抑郁症患者的事件相关电位P300影响。方法:随机将年龄在18～65岁之间符合中国精神障碍分类与诊断标准第3版抑郁症诊断标准患者30例作为研究组,选择30例性别年龄健康者作为对照组。研究组予草酸艾司西酞普兰治疗。两组分别予听觉P300检测,比较P300潜伏期及波幅的差异。结果:研究组Fz、Pz点潜伏期分别为(319±23)ms、(315±20)ms均比对照组分别为(300±22)ms、(299±21)ms延长,研究组Fz、Cz、Pz点分别为(2.5±1.8)μV、(2.6±2.4)μV、(2.5±3.3)μV波幅均比对照组分别为(3.8±2.0)μV、(3.7±1.9)μV、(4.1±3.0)μV降低(P<0.05或P<0.01)。治疗8周后,研究组Fz、Pz点潜伏期分别为(301±19)ms、(305±19)ms]明显缩短,Fz、Cz、Pz点分别为(3.5±1.8)μV、(3.7±2.1)μV、(3.6±3.5)μV波幅明显升高(P<0.05)。结论:抑郁症患者存在P300异常,草酸艾司西酞普兰具有改善这种异常现象的作用。     

Event-related potentials in response to 3-D auditory stimuli

To evaluate auditory spatial cognitive function, age correlations for event-related potentials (ERPs) in response to auditory stimuli with a Doppler effect were studied in normal children. A sound with a Doppler effect is perceived as a moving audio image. A total of 99 normal subjects (age range, 4–21 years) were tested. In the task-relevant oddball paradigm, P300 and key-press reaction time were elicited using auditory stimuli (1000 Hz fixed and enlarged tones with a Doppler effect). From the age of 4 years, the P300 latency for the enlarged tone with a Doppler effect shortened more rapidly with age than did the P300 latency for tone-pips, and the latencies for the different conditions became similar towards the late teens. The P300 of auditory stimuli with a Doppler effect may be used to evaluate auditory spatial cognitive function in children.     

Auditory evoked potentials in borderline personality disorder

Borderline personality disorder is an increasingly recognized condition and frequent management problem in psychiatric and nonpsychiatric practice. Paroxysmal changes in affect and behavior, high incidence of soft neurologic signs and frequent EEG alterations, and evidence of clinical response to antiepileptic drugs have suggested cerebral dysfunction, particularly involving the limbic system or reticular activating system. We recorded early latency brainstem auditory evoked potentials (BAEPs) and long-latency auditory event-related potentials (ERPs) in 20 patients fulfilling DSM-III-R criteria for this disorder. BAEPs were recorded from Cz to ipsilateral and contralateral ear reference, with rarefaction clicks presented at 11.1 per second and 70 dB SL. Two thousand averages were recorded and replicated for each ear, with filter band pass of 150-3000 Hz and 10 ms analysis time. ERPs utilized binaural stimulation with 1000 and 3000 Hz tones in an 80:20 ratio, with interstimulus interval 1.1 second, analysis time 1000 ms, and filter band pass 1-100 Hz. Two hundred averages were recorded and replicated from Cz with linked ear reference. No differences were evident in I-III, III-V, and I-V interpeak latencies between borderline patients and age-matched neurologically and audiologically normal controls. N1, P2, and N2 components of the AEPs were longer in latency and lower in amplitude in borderline patients, while P3 latency was longer and amplitude was attenuated in borderline patients as compared to controls. These findings may suggest differences from normals in attention maintenance and in limbic system function.     

Reduction of the postexcitatory cortical inhibition upon paired-click auditory stimulation in patients with Parkinson’s disease

ObjectivesThe aims of this study were: to investigate the postexcitatory inhibition of cortical evoked potentials on auditory paired-click stimulation in patients with Parkinson’s disease (PD), to analyze the correlation of N1–P2 amplitude ratios (A2/A1) with latency of the P300 auditory event-related potential and to determine the influence of Levodopa intake on postexcitatory inhibition and P300 latency.MethodsThe central (Cz) auditory evoked potentials were recorded in 61 patients with PD and 21 age-matched healthy subjects.ResultsPostexcitatory inhibition in auditory cortex in PD was significantly reduced for interstimulus intervals 500, 700 and 900 ms compared to control group. The degree of this reduction correlated positively with the potential P300 latency and negatively with the summary score of the Mini Mental State Examination (MMSE) which was used to study general cognitive status of the PD patients. Increase of the postexcitatory inhibition towards normal values and decrease of the P300 latency were observed (P < 0.001) following the administration of Levodopa.ConclusionsThe findings of this study testify that inhibitory processes in auditory cortex are deficient in PD patients. The positive effect of Levodopa administration indicates an important role of dopamine-dependent neural mechanisms in modulation of inhibitory processes in the auditory sensory system.SignificanceThe results show that inability of the brain to provide normal inhibition in PD is accompanied by the decline of cognitive indices, including parameters of evoked potential P300 that is related to fundamental aspects of cognitive functions, such as attention and memory.