Altered brain rhythms and functional network disruptions involved in patients with generalized fixation-off epilepsy

Can the aberrant occipital-cerebellum network be a predictor of treatment in panic disorder?

BACKGROUND

This study aimed to detect altered brain activation pattern of patients with panic disorder (PD) and its changes after treatment. The possibilities of diagnosis and prediction of treatment response based on the aberrant brain activity were tested.

METHODS

Fifty-four PD patients and 54 healthy controls (HCs) were recruited. Clinical assessment and resting-state functional magnetic resonance imaging scans were conducted. Then, patients received a 4-week paroxetine treatment and underwent a second clinical assessment and scan. The fractional amplitude of low-frequency fluctuations (fALFF) was measured. Support vector machine (SVM) and support vector regression (SVR) analyses were conducted.

RESULTS

Lower fALFF values in the right calcarine/lingual gyrus and left lingual gyrus/cerebellum IV/V, whereas higher fALFF values in right cerebellum Crus II were observed in patients related to HCs at baseline. After treatment, patients with PD exhibited significant clinical improvement, and the abnormal lower fALFF values in the right lingual gyrus exhibited a great increase. The abnormal fALFF at pretreatment can distinguish patients from HCs with 80 % accuracy and predict treatment response which was reflected in the significant correlation between the predicted and actual treatment responses.

LIMITATIONS

The impacts of ethnic, cultural, and other regional differences on PD were not considered for it was a single-center study.

CONCLUSIONS

The occipital-cerebellum network played an important role in the pathophysiology of PD and should be a part of the fear network. The abnormal fALFF values in patients with PD at pretreatment could serve as biomarkers of PD and predict the early treatment response of paroxetine.

Electroclinical Presentations of Fixation-off Sensitivity in Adults With Symptomatic Epilepsy

PURPOSE

Fixation-off sensitivity (FOS) is a discharge pattern on EEG that occurs owing to the loss of central vision or fixation. Knowledge regarding the relationship between FOS and symptomatic epilepsy is limited. Therefore, we aimed to evaluate the electroclinical features of FOS in adult patients with symptomatic epilepsy.

METHODS

Outpatient video-EEG records of the Hacettepe University Faculty of Medicine were reviewed from 2009 to 2019. Patients aged >18 years with symptomatic epilepsy with a FOS pattern were included. Demographic, clinical, EEG, and neuroimaging data were retrospectively evaluated from an electronic database and patient files.

RESULTS

Eight patients (50% female) were included in this study; seven (87%) had refractory epilepsy. Prominent risk factors were family history of epilepsy in five patients and prenatal/natal insult in four patients. Notable MRI signs included cortical developmental malformation, posterior gliosis, and frontoparietal porencephalic cyst. The FOS pattern was generalized with posterior emphasis in two patients and lateralized or localized in six patients: frontocentroparietal ( n = 1) and temporoparietooccipital ( n = 5). Fixation-off sensitivity discharges were found to be increased by hyperventilation and decreased by drowsiness and sleep in 50% of patients. Fixation-off sensitivity disappeared in one patient with good seizure control.

CONCLUSIONS

In this study, the disappearance of FOS in an epileptic patient with a structural lesion and detection of FOS activity related to a frontoparietal porencephalic cyst were remarkable. Family history of epilepsy was also substantially high. Our results indicate that the underlying mechanism of FOS is much more complicated than previously thought.

Hippocampal cerebral blood flow increased following low-pressure hyperbaric oxygenation in firefighters with mild traumatic brain injury and emotional distress

BACKGROUND

Recent evidence suggests that hyperbaric oxygenation (HBO), which has been used as an effective treatment for certain types of tissue injury, may change neural activities in the human brain and subsequently improve symptoms of psychiatric disorders. To scrutinize the neural mechanism of HBO in the human brain, we investigated whether 20 sessions of HBO changed regional cerebral blood flow (rCBF) of the limbic system in firefighters with mild traumatic brain injury (mTBI) and subjective emotional distress.

METHODS

Twenty firefighters with mTBI and mild emotional distress were treated with HBO at a relatively low pressure of 1.3 atmospheres absolute for 45 min a day for 20 consecutive days (the mild emotional distress group). The rCBF of the limbic system was measured using an arterial spin labeling perfusion magnetic resonance imaging before and after the HBO. Analyses were performed on the data from fourteen individuals who completed the study and 14 age- and sex-matched healthy firefighters (the comparison group).

RESULTS

Firefighters in the mild emotional distress group showed increase rCBF following HBO in a cluster encompassing the right hippocampal and parahippocampal regions (peak t = 4.31; cluster size = 248 mm³)(post-hoc analysis, z = 5.92, p < 0.001) that had lower rCBF relative to the comparison group at baseline (post-hoc analysis, t = -2.20, p = 0.04).

CONCLUSION

The current study demonstrated that low-pressure HBO might increase rCBF of the hippocampal and parahippocampal regions, suggesting a potential underpinning mechanism of HBO in the human brain.