Study design and participants
This case–control study was included fifty (28 men and 22 women) first diagnosed, therapy naïve, HCV patients, aged 20–50, and recruited from the outpatient clinic and department of gastroenterology and hepatology, or referred to the department of neuropsychiatry Kafr Elsheikh University Hospital. In addition, 50 healthy controls matched for age, sex (26 men and 24 women), educational level, and socioeconomic status were included. The study was done for a 1 year from February 2019 to February 2020. A written informed consent was taken from patients and control before participation. This study was approved by the local ethical committee.
Inclusion and exclusion criteria
The inclusion criteria included newly diagnosed HCV (no current or previous treatment with interferon), uncomplicated (Child A, score 6) [26]. The exclusion criteria were patients with cirrhosis or complicated HCV (Child B/C), causes of chronic liver disease (hepatitis B infection, alcohol abuse, parasitic infection, autoimmune disorders, cardiac failure, toxic, and hereditary) psychiatric illness, current substance abuse, renal failure, COPD, uncontrolled DM, other chronic illness that affect cognition (parkinsonism, Alzheimer's, and vascular dementia).
Clinical assessment and investigations
All participants were subjected to the following: full history taking, general medical examination, and complete neurological examination. Laboratory investigations included: HBV surface antigens, anti-HCV antibodies (HCV antibodies done by Beckman colter access immunoassay), PCR viral titer, TSH, random blood glucose, liver function, renal function, and CBC. Abdominal ultrasonography (Philips EPIC 7, Curved probe, 3.5 MHz) was done for evaluation of the liver and exclusion of hepatic cirrhosis or marked fibrosis. MRI of the brain using multiple sequences and planes without contrast on 3 T MRI closed machine to exclude neurological causes of cognitive impairment.
Cognitive assessment
All patients and controls were subjected to cognitive assessment using the following tests:
Mini-mental state examination (MMSE)
This is a rapid screening estimate of cognitive functions that evaluates orientation, attention, working memory, learning, naming, construction, comprehension, and repetition. The total score is 30, with scores less than 24 indicating impaired cognition [27].
Wechsler Memory Scale-Revised (WMS-R) short form
The aim of the test is to provide estimates of various aspects of memory and learning functions (Rabin et al. 2005). WMS-R includes a group of subtests that evaluates figural memory, logical memory, visual paired associate, visual reproduction, and visual memory span [28].
The Wechsler Adult Intelligence Scale (WAIS)-IV Assessment, 2nd Edition
This test provided estimates of the general intellectual function and focused mainly on the difference between verbal IQ and performance IQ scores, and differential characters of subtest [28, 29].
P300 brain wave
Auditory P300-evoked brain potential represents the brain reaction to variable sensory, cognitive, or mechanical stimuli by focusing on the diverse stimuli among the stereotypical ones (the auditory oddball paradigm) [30]. In the auditory oddball task, persons were subjected to a series of high (1000 Hz) “task relevant” target tones and lower (500 Hz) “task irrelevant” tones of 50 ms duration, increase and decrease time, 5 ms, 85 dB, and inter-stimulus interval between 2 and 14 s. The amplitude and the latency of the P300 were estimated by the event-related potentials and the results of P 300 in HCV patients group were compared with the control group (Fig. 1). The test was conducted utilizing quantitative EMG/EP workstations using a Dantec Keypoint (Medtronic, Denmark) device. The test was performed by adding an odd-ball model, as in a set of standard "repeated" stimuli, the subject has to detect an occasionally target stimulus.
Before commencing the examination, the test was first clarified to the patient. Before the wave was registered, the test was replicated many times to ensure the patient understood the process. All of the patients were able to understand the procedure, and each examination would take about 30 min. From scalp electrodes the evoked potential waves were registered with reference electrode position on the ear lobule and a land electrode located on the hand. The active electrode is located along the midline at Oz. The reference electrode is located at location Fz. The subscript z indicates a midline position. The locations of the lateral active electrodes, O 1 O 2 PO 7, and PO 8 are indicated along with the midline active electrode location, O Z. For delivering the auditory stimulus, headphones had been used completely covered the ears. The waves have been classified as N1, P2, N2, P3, and N3 [31]. The measured variables were the P300 latency associated with cognitive processing speed and wave amplitude associated with memory consolidation [32].
Statistical analysis
Data were analyzed using the Statistical Package of Social Science (SPSS) program for Windows (simple edition of the software 21). Qualitative information was described utilizing numbers and percent. Categorical variables were compared by the Chi-square test and Fischer exact test was utilized when expected cell count less than 5. Continuous variables were shown as mean ± SD (standard deviation) for parametric information and median (min–max) for non-parametric information. HCV patients group were compared with the control group by Student t test used for parametric information and Mann Whitney test used for non-parametric information.
Pearson correlation was used to correlate parametric data continuously while using Spearman correlation to correlate non-parametric data continuously. Cutoff points for P 300 latency and amplitude were determined by the ROC curve. Finally, a binary logistic regression analysis was done to establish the ability of the determined cutoff values of P300 latency and amplitude to predict the early cognitive impairment in HCV patients. The threshold of significance is set as a P value < 0.05.