fNIRS-based evaluation of the impact of SARS-CoV-2 infection central auditory processing.

OBJECTIVES: Coronavirus disease-2019 due to SARS-CoV-2 infection has been associated with neurological and neuropsychiatric illnesses as well as auditory system problems. In this study, we aimed to evaluate the impact of SARS-CoV-2 infection on the central auditory system by assessing the hemodynamic activation changes using functional near-infrared spectroscopy (fNIRS). METHODS: Three participants who had SARS-CoV-2 infection (study group) and four participants who had no SARS-CoV-2 infection (control group) were included in the study. During the auditory oddball task in which two different frequencies of tonal stimulation were presented at 80 dB HL, the participants were asked to pay attention to the rare tonal stimulation and mentally count these target stimuli throughout the task. During this task, oxygenated hemodynamic response functions were evaluated with fNIRS. RESULTS: Significantly increased oxygenated hemodynamic responses were observed in both groups during the task (p < .05), which was significantly higher in the study group (p < .05). Significantly more HbO activation was observed in the vmPFC, superior temporal gyrus, and medial temporal gyrus in the study group compared to controls (p < .05). Significantly higher hemodynamic activation was observed in the right hemisphere in both groups, which was significantly higher in the study group (p < .05). CONCLUSION: SARS-CoV-2 infections may impact on central auditory processing or auditory attention due to changes in oxyhemoglobin levels in the frontal and temporal brain regions. It seems that SARS-CoV-2 infection is associated with an additional load on neural activity, and difficulties in focusing in auditory attention, following speech and hearing in noise as well as increased effort to perceive auditory cues.

Low frequency oscillations during hand laterality judgment task with and without personal perspectives: a preliminary study.

Sense of personal perspective is crucial for understanding in attentional mechanisms of the perception in "self" or "other's" body. In a hand laterality judgment (HLJ) task, perception of perspective can be assessed by arranging angular orientations and depths of images. A total of 11 healthy, right-handed participants (8 females, mean age: 38.36 years, education: 14 years) were included in the study. The purpose of this study was to investigate behavioural and cortical responses in low-frequency cortical rhythms during a HLJ task. A total of 80-visual hand stimuli were presented through the experiment. Hand visuals were categorized in the way of side (right vs. left) and perspective (1st vs. 3rd personal perspective). Both behavioural outcomes and brain oscillatory characteristics (i.e., frequency and amplitude) of the Electroencephalography were analysed. All reaction time and incorrect answers for 3rd person perspective were higher than the ones for 1st person perspective. Location effect was statistically significant in event-related theta responses confirming the dominant activity of theta frequency in spatial memory tasks on parietal and occipital areas. In addition, we found there were increasing in delta power and phase in hand visuals with 1st person perspective and increasing theta phase in hand visuals with 3rd person perspective (p < 0.05). Accordingly, a clear dissociation in the perception of perspectives in low-frequency bands was revealed. These different cortical strategy in the perception of hand visual with and without perspectives may be interpreted as delta activity may be related in self-body perception, whereas theta activity may be related in allocentric perception.

The effects of cognitive, physical, and somatosensory rehabilitation after right temporo-parietal tumor resection on cognitive, motor, somatosensory, and electrophysiological parameters: A case report.

INTRODUCTION: This report examines the effects of a multimodal rehabilitation program which includes cognitive, physical, and somatosensory rehabilitation after right temporo-parietal tumor resection on cognitive, motor, somatosensory, and electrophysiological parameters. CASE DESCRIPTION: A 22-year-old patient presented with sensory loss in the dominant left hand and reduced writing ability after right temporo-parietal lobe resection. Cognitive, motor, and sensory evaluations were carried out pre and post-treatment. The patient's spontaneous electroencephalo-gram (EEG) and an EEG during application of transcutaneous electrical nerve stimulation (TENS) (TENS EEG) were recorded. As a reference for the patient's electrophysiological values, EEGs of 4 healthy individuals were also taken. Over a period of 1 year, the patient received multimodal rehabilitation which includes cognitive, physical, and somato-sensory rehabilitation on 2 days each week. OUTCOMES: An improvement of the patient's cognitive capacities, motor strength, superficial, deep and cortical sensations was achieved. After rehabilitation, an increase in parietal and occipital alpha activity as well as in frontal and parietal beta activity was seen both in spontaneous EEG and in TENS EEG. With increasing TENS intensity, alpha and beta power increased as well. CONCLUSION: Our findings suggest that a multimodal rehabilitation program may improve cognitive, sensory, and motor effects after resection due to tumor surgery.

Plasma homocysteine levels in patients treated with levodopa: motor and cognitive associations.

OBJECTIVE: The aim of this study was to determine whether hyperhomocysteinemia caused by levodopa used in idiopathic Parkinson's disease (IPD) is associated with cognitive or physical impairments. The role of folate and vitamin B12 levels in this context was also ascertained. METHODS: Thirty-nine patients who had been followed with the diagnosis of IPD in our clinic for > 2 years and 28 healthy control subjects with similar demographic features were included in the study. The homocysteine, folic acid and vitamin B12 levels and the results of the short test of mental status (STMS) and the clock drawing test of IPD patients were compared with those of the controls. Subsequently, the patients with a homocysteine level of >14 micromol/l were compared with those having a homocysteine level of <14 micromol/l by means of detailed neuropsychometric test batteries. RESULTS: Homocysteine levels were significantly higher in the patient group in comparison with the controls. There was a negative correlation between hyperhomocysteinemia and the levels of vitamin B12 and folate. On the other hand, a positive correlation between hyperhomocysteinemia and the levodopa dose was detected. There was a positive correlation between hyperhomocysteinemia and unified Parkinson's disease rating scale (UPDRS) motor section. The critical dose of levodopa was observed to be 300 mg/d. In terms of cognitive and frontal functions, no significant difference was detected between the patients and control group. The subgroup with a homocysteine level of >14 micromol/l had a significantly poorer performance in frontal and memory tests. DISCUSSION: In patients with IPD who are detected to have hyperhomocysteinemia, the assessment of the cognitive performance, folic acid and vitamin B12 levels and the supplementation of folic acid and vitamin B12 to the treatment regimen might be appropriate.