Cognitive function and quantitative electroencephalogram analysis in subjects recovered from COVID-19 infection.

BACKGROUND & OBJECTIVES: Objective assessment of post-COVID-19 cognitive dysfunction is highly warranted. This study aimed to evaluate the cognitive dysfunction of COVID-19 survivors with cognitive complaints, both clinically and neurophysiologically, using Quantitative Electroencephalogram (QEEG). METHODS: This case-control study was conducted on 50 recovered subjects from COVID-19 infection with cognitive complaints and 50 age, sex, and educational-matched healthy controls. Both groups were subjected to the following neurocognitive tests: Paired associate learning Test (PALT) and Paced Auditory Serial Addition Test (PASAT). The neurophysiological assessment was also done for both groups using QEEG. RESULTS: COVID-19 survivors had significantly lower PALT scores than controls (P < 0.001). QEEG analysis found significantly higher levels of Theta / Beta ratio in both central and parietal areas in patients than in the controls (P < 0.001 for each). The interhemispheric coherence for the frontal, central, and parietal regions was also significantly lower in patients than in the control group regarding alpha and beta bands. There were statistically significant lower scores of PALT and PASAT among cases with severe COVID-19 infection (P = 0.011, 0.005, respectively) and those who needed oxygen support (P = 0.04, 0.01, respectively). On the other hand, a statistically significantly lower mean of frontal alpha inter-hemispheric coherence among patients with severe COVID-19 infection (P = 0.01) and those needing mechanical ventilation support (P = 0.04). CONCLUSION: Episodic memory deficit is evident in COVID-19 survivors with subjective cognitive complaints accompanied by lower inter-hemispheric coherence in frontal regions. These clinical and neurophysiological changes are associated with hypoxia and COVID-19 severity.

Comparative effect of deliberate hypotensive anesthesia using nitroglycerine vs. phentolamine on event related potentials and cognitive functions in patients undergoing septoplasty: a randomized controlled trial.

BACKGROUND: Postoperative cognitive dysfunction is a noteworthy complication of deliberate hypotensive anesthesia. The aim of this work was to compare the effect of deliberate hypotensive anesthesia using nitroglycerine versus phentolamine on event-related potentials and cognitive function in patients undergoing septoplasty surgery. METHODS: This prospective randomized controlled trial was conducted on 80 patients indicated for septoplasty under general anesthesia; 40 patients received intra-operative Nitroglycerine and 40 patients received intra-operative Phentolamine. Cognitive assessment (using Paired Associate Learning test (PALT) and Benton Visual Retention test (BVRT)) and P300 recording were done for all included patients pre-operatively and one week postoperatively. RESULTS: The scores of PALT and Benton BVRT significantly declined one week following surgery in both Nitroglycerine and Phentolamine groups. There was no statistically significant difference between Nitroglycerine and Phentolamine groups in the postoperative decline in either PALT or BVRT (P-value = 0.342, 0.662 respectively). The values of P300 latency showed a significant delay one week following surgery in both Nitroglycerine and Phentolamine groups (P-value ≤ 0.001, 0.001), but in Nitroglycerine group, the delay is significantly higher than in Phentolamine group (P-value = 0.003). The values of P300 amplitude significantly decreased one week following surgery in both Nitroglycerine and Phentolamine groups (P-value ≤ 0.001, 0.001), but there was no statistically significant difference between Nitroglycerine and Phentolamine groups (P-value = 0.099). CONCLUSION: Phentolamine is preferred over nitroglycerin in deliberate hypotensive anesthesia because it has less harmful effect on cognitive function than nitroglycerin.

Postoperative cognitive dysfunction and the possible underlying neurodegenerative effect of anaesthesia.

Introduction: There is alarming evidence about the involvement of general anaesthesia in the development of postoperative cognitive dysfunction. Aim: To clarify the impact of general anaesthesia on cognitive function and to study the possible effect of general anaesthesia on serum S100B, the marker of neuronal degeneration. Methods: This is a prospective randomised controlled study carried out on 50 patients undergoing elective laparoscopic cholecystectomy under conventional general anaesthesia. Cognitive assessment for selected patients was done preoperative and 1 week postoperative using Paired Associate Learning test (PALT) for assessment of verbal memory and Benton Visual Retention test (BVRT) for assessment of visual memory. Quantitative determination of serum S100B was done for all patients in the basal sample and postoperative sample by applying an enzyme- linked immunoabsorbent assay technique on am automated ELISA platform. Results: Regarding cognitive tests, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (p-value = .012). There was also a statistically significant difference between the mean value of preoperative BVRT and postoperative BVRT (p-value = .011). Regarding S100B, there was a statistically significant difference between preoperative and postoperative serum level (p-value = .002). There was also a statistically significant negative correlation between postoperative S100B serum level and the postoperative scores of both PALT and BVRT. Conclusion: General anaesthesia is incriminated in the development of postoperative verbal and visual memory impairment and in the postoperative increase in serum S100B, the markers of neuronal degeneration.

Effect of local anesthesia (with lidocaine vs bupivacaine) on cognitive function in patients undergoing elective cataract surgery.

PURPOSE: Postoperative cognitive dysfunction has gained much attention over the last years. Multiple clinical trials have attempted to differentiate the effect of local vs general anesthesia on postoperative cognitive function. The aim of this work was to study the effect of local anesthesia with lidocaine vs bupivacaine on cognitive function. PATIENTS AND METHODS: This was a prospective randomized trial carried out on 61 patients undergoing elective cataract surgery by phacoemulsification under local anesthesia. Twenty-eight patients received lidocaine 2% and 33 patients received bupivacaine 0.5%. Cognitive assessment for all patients was done preoperatively and 1 week postoperatively using paired associate learning test (PALT) and category verbal fluency (VF) test (animal category). RESULTS: Regarding cognitive assessment of patients in lidocaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.004), and between the mean value of preoperative VF and postoperative VF (P-value =0.002). As for bupivacaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.021), and between the mean value of preoperative VF and postoperative VF (P-value =0.037). On comparing lidocaine and bupivacaine groups in pre and postoperative PALT & VF scores, there was no statistically significant difference between both groups. CONCLUSION: Both lidocaine and bupivacaine caused postoperative cognitive impairment. Lidocaine was found to have a worse effect on cognitive function than bupivacaine, but the difference was not statistically significant.

Comparative Effect of Local Anesthesia with Lidocaine 2% Versus Topical Anesthesia on Cognitive Function in Ophthalmic Surgery.

BACKGROUND: Multiple clinical trials targeted the assessment of cognitive function following local versus general anesthesia in patients undergoing ophthalmic surgery, but no previous clinical trials have focused on the effect of topical anesthesia on cognitive function. OBJECTIVES: This study aimed to compare the effect of local anesthesia with lidocaine 2% versus topical anesthesia with Oxybuprocaine (benoxinate hydrochloride 0.4%) on cognitive function in patients undergoing elective cataract surgery. METHODS: This is a prospective randomized clinical trial carried out on 60 patients undergoing elective cataract surgery by phacoemulsification. Thirty patients received local anesthesia with lidocaine 2% and thirty patients received topical anesthesia with Oxybuprocaine (benoxinate hydrochloride 0.4%). Patients' satisfaction was assessed postoperatively using the Iowa satisfaction with anesthesia scale (ISAS). Cognitive assessment for all patients was done preoperatively and 1 week postoperatively using paired-associate learning test (PALT) and category verbal fluency (VF) test (animal category). RESULTS: There was no statistically significant difference between local and topical anesthesia groups in the mean of responses to the 11 statements of ISAS (P = 0.071). Regarding cognitive assessment, there was a statistically significant postoperative decline in the local anesthesia group in both PALT scores (P = 0.005) and VF scores (P = 0.01). In the topical anesthesia group, there was no statistically significant difference between pre- and postoperative PALT scores (P = 0.326) or VF scores (P = 0.199). CONCLUSIONS: Postoperative cognitive dysfunction following elective cataract surgeries under local anesthesia can be attributed to the effect of local anesthesia rather than the effect of surgery.