Intracranial recordings in humans reveal specific hippocampal spectral and dorsal vs. ventral connectivity signatures during visual, attention and memory tasks

Invasive brain recordings using many electrodes across a wide range of tasks provide a unique opportunity to study the role of oscillatory patterning and functional connectivity. We used large-scale recordings (stereo EEG) within and beyond the human hippocampus to investigate the role of distinct frequency oscillations during real-time execution of visual, attention and memory tasks in eight epileptic patients. We found that activity patterns in the hippocampus showed task and frequency dependent properties. Importantly, we found distinct connectivity signatures, in particular concerning parietal-hippocampal connectivity, thus revealing large scale synchronization of networks involved in memory tasks. Comparing the power per frequency band, across tasks and hippocampal regions (anterior/posterior) we confirmed a main effect of frequency band (p = 0.002). Gamma band activity was higher for visuo-spatial memory tasks in the anterior hippocampus. Further, we found that alpha and beta band activity in posterior hippocampus had larger modulation for high memory load visual tasks (p = 0.004). Three functional connectivity task related networks were identified: (dorsal) parietal-hippocampus (visual attention and memory), ventral stream- hippocampus and hippocampal-frontal connections (mainly tasks involving face recognition or object based search). These findings support the critical role of oscillatory patterning in the hippocampus during visual and memory tasks and suggests the presence of task related spectral and functional connectivity signatures. These results show that the use of large scale human intracranial recordings can validate the role of oscillatory and functional connectivity patterns across a broad range of cognitive domains.

Transoral video assisted thyroidectomy: a systematic review

INTRODUCTION

The aim of this study is to perform a review of the English-language international literature concerning thyroid surgery performed through the transoral vestibular approach, to evaluate its flessibility and safety in terms of complications.

MATERIALS AND METHOD

The review was carried out on 17 studies of 17 different Authors. The following variables were taken into consideration: first Author's name, nationality, year of publication, number of cases, hospital stay, conversion rate, type of surgical approach, total number of total thyroidectomies and loboisthmectomies, operative time range, intraoperative blood loss range, number and percentage of complications.

RESULTS

736 procedures were performed: 289 total thyroidectomies and 447 loboisthmectomies. Surgical approach was trivestibular in 15 cases and combined (oro-vestibular) in 2 cases. The operative time varies from 43 minutes for a loboisthmectomy to 345 for a total thyroidectomy. Intraoperative blood loss ranges from 3 to 300 ml. Ten cases were converted into open surgery. The hospital stay varies from 1 to 10 days. Complications were: transient recurrent laryngeal nerve palsy in 34 cases, permanent in 2 cases; transient hypoparathyroidism in 62 cases. One case of postoperative bleeding, 22 postoperative seroma, 20 cases of mental nerve injury, 8 cases of operative wound infection.

CONCLUSIONS

Transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a new surgical method, the use of which exclusively meets the aesthetic needs of some patients. Its specific complication is the injury of the mental nerves. Further studies, however, seem to be necessary, on numerically broader cases, to ascertain the real validity of the method.

Early discharge after total thyroidectomy: a retrospective feasibility study

AIM

The continued hospitalization after total thyroidectomy is often due to the onset of hypocalcemic complications more than 24 hours after surgery. So it would be important to predict which patients will not develop the hypocalcemic complication to discharge them early. This was the aim of our study.

PATIENTS AND METHODS

Our retrospective study was conducted on 327 consecutive thyroidectomized patients, operated on for benign and malignant diseases. We evaluated the values of preoperative serum calcium levels (Cal0) and of the first postoperative day (Cal1) and two new variables were calculated (dCal and dCaln). The same thing was made on a subgroup of 111 patients in whom also parathiroyd hormone (PTH) values were detected. Statistical analysis was performed with the goal of determining if we could establish a safe criterion for discharge at 24 hours after surgery and if there is a correlation between suitability for discharge and diagnosis.

RESULTS

As to discharge, the predictive power of the discriminant function applied was significant both on the total of patients and in the subgroup of 111 patients, but it was clinically unacceptable because it would expose us to a 21% to 27% error rate. It is not possible to identify a threshold, below which to consider patients surely dischargeable. The diagnosis does not appear correlated with the suitability for discharge.

CONCLUSION

On the basis of serum calcium and PTH levels in the first postoperative day, it is impossible to predict which patients can be discharged 24 hours after surgery without incurring in hypocalcemic complications.

Current standards of neuropsychological assessment in epilepsy surgery centers across Europe

We explored the current practice with respect to the neuropsychological assessment of surgical epilepsy patients in European epilepsy centers, with the aim of harmonizing and establishing common standards. Twenty-six epilepsy centers and members of "E-PILEPSY" (a European pilot network of reference centers in refractory epilepsy and epilepsy surgery), were asked to report the status of neuropsychological assessment in adults and children via two different surveys. There was a consensus among these centers regarding the role of neuropsychology in the presurgical workup. Strong agreement was found on indications (localization, epileptic dysfunctions, adverse drugs effects, and postoperative monitoring) and the domains to be evaluated (memory, attention, executive functions, language, visuospatial skills, intelligence, depression, anxiety, and quality of life). Although 186 different tests are in use throughout these European centers, a core group of tests reflecting a moderate level of agreement could be discerned. Variability exists with regard to indications, protocols, and paradigms for the assessment of hemispheric language dominance. For the tests in use, little published evidence of clinical validity in epilepsy was provided. Participants in the survey reported a need for improvement concerning the validity of the tests, tools for the assessment of everyday functioning and accelerated forgetting, national norms, and test co-normalization. Based on the present survey, we documented a consensus regarding the indications and principles of neuropsychological testing. Despite the variety of tests in use, the survey indicated that there may be a core set of tests chosen based on experience, as well as on published evidence. By combining these findings with the results of an ongoing systematic literature review, we aim for a battery that can be recommended for the use across epilepsy surgical centers in Europe.

Fluency tasks generate beta-gamma activity in language-related cortical areas of patients during stereo-EEG monitoring

A quantitative method was developed to map cortical areas responsive to cognitive tasks during intracerebral stereo-EEG recording sessions in drug-resistant patients candidate for epilepsy surgery. Frequency power changes were evaluated with a computer-assisted analysis in 7 patients during phonemic fluency tasks. All patients were right-handed and were explored with depth electrodes in the dominant frontal lobe. We demonstrate that fluency tasks enhance beta-gamma frequencies and reduce background activities in language network regions of the dominant hemisphere. Non-reproducible changes were observed in other explored brain areas during cognitive tests execution.

Fine needle aspiration cytology of 650 thyroid nodules operated for multinodular goiter: a cyto-histological correlation based on the new Italian cytological classification (siapec 2014)

The new Italian cytological classification (SIAPEC 2014) of thyroid nodules, in line with those of Bethesda and BTA-RCPath, replaces the previous TIR3 class with two new classes (TIR3A and TIR3B), which correspond to different risks of malignancy and clinical actions required. The present study was conducted to evaluate the diagnostic accuracy of the new SIAPEC classification as opposed to its previous version (SIAPEC 2007). Preoperative cytology was compared with the final histology obtained from 650 consecutive patients who underwent total thyroidectomy for multinodular goiter. Of this total, 434 patients (group A) had their cytological diagnosis based on the old SIAPEC 2007 classification and 216 patients (group B) had their cytological diagnosis based on the SIAPEC 2014 classification. In group A 111 patients (25.6%) had a TIR3 diagnosis, while in group B 52 patients (24.1%) received a TIR3 diagnosis, of whom 30 had TIR3A and 22 had TIR3B. In group A, 46 (41.4%) out of the 111 patients with TIR3 diagnosis had, based on histology, a thyroid carcinoma. In group B, only 2 (6.7%) out of 30 patients with TIR3A diagnosis had a thyroid carcinoma. This rate of malignancy was significantly lower (p less than 0.001) than that observed in patients with TIR3B diagnosis, in which 12 (54.5%) out of 22 patients had a carcinoma. The observations here reported show that, in respect to the previous version, the new Italian cytological classification provides greater diagnostic accuracy for detecting thyroid nodule malignancy.