Distinguishing acute-onset CIDP from Guillain-Barré syndrome with treatment related fluctuations

Guillain-Barré syndrome (GBS) patients may worsen after initial treatment (treatment-related fluctuation [TRF]). It is difficult to distinguish GBS-TRF from chronic inflammatory demyelinating polyneuropathy with acute onset (A-CIDP). The authors compared 13 patients with A-CIDP with 11 patients with GBS-TRF and concluded that A-CIDP should be suspected when a patient with GBS deteriorates after 9 weeks from onset or when deterioration occurs three times or more. Maintenance treatment should then be considered.     

Aberrant temporal–spatial complexity of intrinsic fluctuations in major depression

European Archives of Psychiatry and Clinical Neuroscience - Accumulating evidence suggests that the brain is highly dynamic; thus, investigation of brain dynamics especially in brain connectivity...     

Fractional amplitude of low-frequency fluctuations is disrupted in Alzheimer’s disease with depression

Objective

To explore brain activity in AD with depression (D-AD) based on fractional amplitude of low-frequency fluctuation (fALFF).

Contributions of tidal lung inflation to human R–R interval and arterial pressure fluctuations

We studied the effects of mechanical lung inflation on respiratory frequency R–R interval and arterial pressure fluctuations in nine healthy young adults undergoing elective orthopedic surgery. We conducted this research to define the contribution of pulmonary and thoracic stretch receptor input to respiratory sinus arrhythmia. We compared fast Fourier transform spectral power during three modes of ventilation: (1) spontaneous, frequency-controlled (0.25 Hz) breathing, (2) intermittent positive pressure ventilation (0.25 Hz, with a tidal volume of 8 ml/kg) and (3) high frequency jet ventilation (5.0 Hz, 2.5 kg/cm²), after sedation and vecuronium paralysis. Mean R–R intervals, arterial pressures and arterial blood gas levels were comparable during all three breathing conditions. Respiratory frequency systolic pressure spectral power was comparable during spontaneous breathing and conventional mechanical ventilation, but was significantly reduced during high frequency jet ventilation (P<0.05). Respiratory frequency R–R interval spectral power (used as an index of respiratory sinus arrhythmia) declined dramatically with sedation and muscle paralysis (P<0.05), but was greater during conventional mechanical, than high frequency jet ventilation (P<0.05). These results suggest that although phasic inputs from pulmonary and thoracic stretch receptors make a statistically significant contribution to respiratory sinus arrhythmia, that contribution is small.     

Does timing and dosage of levodopa modify drug-induced dyskinesias and motor fluctuations? A retrospective analysis

The aim of this study was to verify the influence of levodopa treatment in the development of long-term complications of Parkinson's disease (PD). We retrospectively analysed several epidemiological characteristics of the disease including long-term motor complications with timing and dose of levodopa in 50 patients. No differences between timing and initial dosage of levodopa were observed in patients who developed dyskinesias or motor fluctuations and those who did not. The patients who developed dyskinesias were younger and the rate of decline was faster in patients who developed motor fluctuations. These results suggest that late complications of levodopa are independent of the timing and initial dosage.     

How default is the default mode of brain function? Further evidence from intrinsic BOLD signal fluctuations

The default mode of brain function hypothesis and the presence of spontaneous intrinsic low-frequency signal fluctuations during rest have recently attracted attention in the neuroscience community. In this study we asked two questions: First, is it possible to attenuate intrinsic activity in the self-referential, default mode of brain function by directing the brains resources to a goal-oriented and attention-demanding task? Second, what effect does a sustained attention-demanding overt task performance have on the two intrinsically active networks in the brain, those being the task-negative, default-mode and the anticorrelated, task-positive network? We used functional magnetic resonance imaging to monitor spontaneous intrinsic activity during rest and sustained performance of a sequential two-back working memory task. We compared intrinsic activity during rest and the two-back task to the signal increases and decreases observed in an epoch-related version of the working memory task. Our results show that spontaneous intrinsic activity in the default-mode network is not extinguished but rather attenuated during performance of the working memory task. Moreover, we show that the intrinsic activity in the task-positive network is reorganized in response to the working memory task. The results presented here complements earlier work that have shown that task-induced signal deactivations in the default-mode regions is modulated by cognitive load to also show that intrinsic, spontaneous signal fluctuations in the default-mode regions persist and reorganize in response to changes in external work load.     

Motor fluctuations and dyskinesias in advanced/end stage Parkinson’s disease: a study from a population of brain donors

Summary. Treatment-related motor fluctuations (MFs) and dyskinesias are considered one of the most important problems in the long-term management of Parkinson’s disease (PD). However, only a few studies have focused on their characteristics during advanced and end stages of the disease. We therefore assessed MFs and dyskinesias in a cohort of 61 late/end stage patients with a clinical and pathological diagnosis of PD and investigated the influence of disease- and treatment-related variables on their occurrence. A total of 62.3% of our patients experienced “wearing-off” phenomena, 68.9% “on-off” motor fluctuations and 60.7% dyskinesias at advanced/end stage disease. Age at disease onset and disease duration were significantly associated with dyskinesias. A substantial number of patients experienced spontaneous resolution of their motor complications during the last two years of their disease without treatment modifications. The clinical heterogeneity of treatment-related motor complications in PD points towards a complex mechanism for their etiopathogenesis. Although advanced disease and L-dopa administration are closely tied to their development, other mechanisms involving synaptic aging, altered neuronal plasticity and post-synaptic degeneration may be involved.     

Correction to: Abnormal regional homogeneity (ReHo) and fractional amplitude of low frequency fluctuations (fALFF) in first-episode drug-naïve schizophrenia patients comorbid with depression

Brain Imaging and Behavior -     

Is there a difference in gastric emptying between Parkinson’s disease patients under long-term <Emphasis Type="SmallCaps">l</Emphasis>-dopa therapy with and without motor fluctuations? An analysis using the <Superscript>13</Superscript>C-acetate breath test

The mechanism underlying the motor fluctuations that develop after long-term l-dopa therapy is not fully known. It has been speculated that malabsorption of l-dopa from the small intestine occurs. It was reported that gastric retention in Parkinson’s disease (PD) patients with motor fluctuations is increased as compared with that in PD without fluctuations. Because l-dopa therapy may worsen the symptoms of delayed gastric emptying (GE), it was not clear whether the delayed GE of PD patients with motor fluctuation was affected by l-dopa therapy. We assessed GE in PD patients with and without motor fluctuations. We investigated GE in 40 patients with PD under long-term l-dopa therapy, 20 fluctuators with “delayed-on” and “no-on” phenomena, 20 nonfluctuators, and 20 healthy volunteers. GE was examined by the ¹³C-acetate breath test (¹³C-ABT) [the half emptying time (HET), the peak time of the ¹³C-%-dose-excess curve (T _max)], with expirations collected for 4 h after a test meal and analyzed for ¹³CO₂ using an infrared (IR) spectrophotometer. The T _max of GE as assessed using the ¹³C-ABT was significantly delayed in all PD patients as compared with controls (P = 0.002). The HET was significantly delayed in all PD patients as compared with controls (P < 0.001). The T _max and HET were not significantly delayed in PD patients with motor fluctuations as compared with PD patients without motor fluctuations. These results demonstrated that GE is commonly delayed in PD patients with long-term l-dopa therapy. Delayed GE does not differ between PD patients with and without motor fluctuations. This finding demonstrated that the motor fluctuation in PD may not be influenced by GE.