COVID-19 and early-stage lung cancer both featuring ground-glass opacities: a propensity score-matched study.

BACKGROUND: Radiological manifestations of coronavirus disease 2019 (COVID-19) featured ground-glass opacities (GGOs), especially in the early stage, which might create confusion in differential diagnosis with early lung cancer. We aimed to specify the radiological characteristics of COVID-19 and early lung cancer and to unveil the discrepancy between them. METHODS: One hundred and fifty-seven COVID-19 patients and 374 early lung cancer patients from four hospitals in China were retrospectively enrolled. Epidemiological, clinical, radiological, and pathological characteristics were compared between the two groups using propensity score-matched (PSM) analysis. RESULTS: COVID-19 patients had more distinct symptoms, tended to be younger (P<0.0001), male (P<0.0001), and had a higher body mass index (P=0.014). After 1:1 PSM, 121 matched pairs were identified. Regarding radiological characteristics, patients with a single lesion accounted for 17% in COVID-19 and 89% in lung cancer (P<0.0001). Most lesions were peripherally found in both groups. Lesions in COVID-19 involved more lobes (median 3.5 vs. 1; P<0.0001) and segments (median 6 vs. 1; P<0.0001) and tended to have multiple types (67%) with patchy form (54%). Early lung cancer was more likely to have a single type (92%) with oval form (66%). Also, COVID-19 and early lung cancer either had some distinctive features on computed tomography (CT) images. CONCLUSIONS: Both COVID-19 and early lung cancers showed GGOs, with similar but independent features. The imaging characteristics should be fully understood and combined with epidemiological history, pathogen detection, laboratory tests, short-term CT reexamination, and pathological results to aid differential diagnosis.

Effects of Risperidone and Paliperidone on Brain-Derived Neurotrophic Factor and N400 in First-Episode Schizophrenia.

BACKGROUND: Risperidone and paliperidone have been the mainstay treatment for schizophrenia and their potential role in neuroprotection could be associated with brain-derived neurotrophic factor (BDNF) and N400 (an event-related brain potential component). So far, different effects on both BDNF and N400 were reported in relation to various antipsychotic treatments. However, few studies have been conducted on the mechanism of risperidone and paliperidone on BDNF and N400. This study aimed to compare the effects of risperidone and paliperidone on BDNF and the N400 component of the event-related brain potential in patients with first-episode schizophrenia. METHODS: Ninety-eight patients with first-episode schizophrenia were randomly divided into the risperidone and paliperidone groups and treated with risperidone and paliperidone, respectively, for 12 weeks. Serum BDNF level, the latency, and amplitude of the N400 event-related potential before and after the treatment and Positive and Negative Syndrome Scale (PANSS) scores were compared between the two groups. RESULTS: A total of 94 patients were included in the final analysis (47 patients in each group). After the treatment, the serum BDNF levels in both groups increased (all P < 0.01), while no significant difference in serum BDNF level was found between the groups before and after the treatment (all P > 0.05). After the treatment, N400 amplitudes were increased (from 4.73 ± 2.86 µv and 4.51 ± 4.63 µv to 5.35 ± 4.18 µv and 5.52 ± 3.08 µv, respectively) under congruent condition in both risperidone and paliperidone groups (all P < 0.01). Under incongruent conditions, the N400 latencies were shortened in the paliperidone group (from 424.13 ± 110.42 ms to 4.7.41 ± 154.59 ms, P < 0.05), and the N400 amplitudes were increased in the risperidone group (from 5.80 ± 3.50 µv to 7.17 ± 5.51 µv, P < 0.01). After treatment, the total PANSS score in both groups decreased significantly (all P < 0.01), but the difference between the groups was not significant (P > 0.05). A negative correlation between the reduction rate of the PANSS score and the increase in serum BDNF level after the treatment was found in the paliperidone group but not in the risperidone group. CONCLUSIONS: Both risperidone and paliperidone could increase the serum BDNF levels in patients with first-episode schizophrenia and improve their cognitive function (N400 latency and amplitude), but their antipsychotic mechanisms might differ.

Effects of Repetitive Transcranial Magnetic Stimulation Treatment on Event-Related Potentials in Schizophrenia.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) and event-related potentials (ERPs) are a noninvasive technique that widely used in neurophysiological field. Although rTMS has shown clinical utility for a number of neurological conditions, Recently,there was little understanding of the the efficacy of rTMS on Schizophrenia(SZ) and the change of ERP between before and after rTMS treatment. The objective of this study was to investigate the characteristics of N400, mismatch negativity (MMN), and P300 before and after treatment with rTMS in SZ. METHODS: One hundred and twenty-seven SZ patients hospitalized in Shanghai Mental Health Center from March 2015 to July 2017, divided into two groups (85 patients were recruited as rTMS group and 42 were recruited as sham rTMS [ShrTMS] group) and 76 normal controls (NCs) who were the staff and refresher staff in our hospital were recruited at the same time. A Chinese-made rTMS and a Runjie WJ-1 ERPs instrument were used in the present experiment. N400 was elicited by congruent and noncongruent Chinese idioms. After rTMS treatment, N400, P300, and MMN characteristics were compared with those before treatment and NC group. RESULTS: Compared with NC, the SZ patients exhibited delays in N400, P300, and MMN latency and decreased N400, P300, and MMN amplitudes in their frontal area (P < 0.05). After 25 rTMS treatments, N400 amplitudes in the frontal area (elicited by idioms with same phonic and different shape and meaning and with different phonic, shape, and meaning) were increased in the SZ patients (P < 0.05). However, there was no significant change in N400 before and after treatment with ShrTMS in SZ patients (P > 0.05). Amplitudes for MMN and target P300 also increased in SZ patients after rTMS treatment (P < 0.05). CONCLUSIONS: Based on our preliminary findings, we believe that the combined usage of N400, MMN, and P300 could be a valuable index and an electrophysiological reference in evaluating the effects of rTMS treatment in SZ patients.

Follow-up of N400 in the Rehabilitation of First-episode Schizophrenia.

BACKGROUND: The N400 component of event-related potentials (ERP) has recently drawn widespread attention at home and abroad. This study was to explore the relationship between N400 changes and risperidone treatment and rehabilitation infirst-episode schizophrenia (FES). METHODS: ERP component N400 was recorded by Guangzhou Runjie WJ-1 ERP instruments, in 58 FES before and 6 months, 15 months after risperidone treatment, and in 62 normal controls. The patients' syndromes were assessed by Positive and Negative Syndrome Scale (PANSS). And the stimuli are Chinese sentences with matching (congruent) or mismatching (incongruent) ending words. RESULTS: N400 latencies were prolonged, and amplitudes were decreased in Cz, Pz, Fz, C3, C4, in FES compared with in NC, before treatment. The prolonged N400 latencies and decreased amplitudes were negatively correlated with the patients' positive scale and total scale of PANSS. There are significant differences of N400 amplitudes and latencies in 6 months and 15 months follow-up after treatment. Before treatment, 6 months and 15 months after treatment, N400 latencies are 446 ± 35 ms, 440 ± 37 ms, 414 ± 31 ms (F = 9.72, P < 0.01) in incongruent situation; N400 amplitudes are 5.2 ± 4.6 µV, 5.7 ± 4.8 µV, 7.3 ± 5.0 µV (F = 2.06, P > 0.05) in congruent situation, and 8.5 ± 5.9 µV, 10.1 ± 5.0 µV, 11.9 ± 7.0 µV (F = 3.697, P < 0.05) in incongruent situation. CONCLUSIONS: N400 could be used to predict the effects of treatment of schizophrenia to some degree. The linguistic and cognitive impairment in schizophrenia can be improved by antipsychotic drugs.

Nonlinear dynamics of electroencephalography study in schizophrenic patients.

BACKGROUND: Few characteristic changes of linear electroencephalograph (EEG) have been reported in schizophrenia. The aim of the present study was to investigate the changes in temporal-spatial dimensional properties of EEG under different cognitive tasks in patients with schizophrenia. METHODS: EEG was recorded by using EEG-1518K system and mapping system (Nihon Kohden Tomioka Corporation, Japan) in 45 schizophrenic patients and 47 healthy adults (normal control, NC) under five states: eyes closed, eyes open, mental arithmetic test with eyes closed, memory test with eyes open, and number cancellation test. Correlation dimension (D2) and point-wise correlation dimension (PD2) were calculated for all EEG analyses. RESULTS: (1) There were no significant differences of D2 and PD2 between NC and schizophrenic patients under states of eyes open and closed. (2) Compared with NC, schizophrenic patients showed decreased performance of D2 in mental arithmetic test with eyes closed and number cancellation test (mental arithmetic test with eyes closed: Nc 5.9 ± 0.6, Sch 3.0 ± 0.8; number cancellation test: Nc 6.0 ± 0.6, Sch 4.4 ± 0.7; P < 0.05 or P < 0.01). (3) Schizophrenic patients also showed decrease performance of PD2 in mental arithmetic test with eyes closed, memory test with eyes open, and number cancellation test (mental arithmetic test with eyes closed: Nc 6.9 ± 0.7, Sch 4.0 ± 0.8; memory test with eyes open: Nc 6.6 ± 0.8, Sch 5.0 ± 0.9; number cancellation test: Nc 7.1 ± 0.7, Sch 4.8 ± 0.9; P < 0.05 or P < 0.01). CONCLUSIONS: Nonlinear dynamic analysis provided a new approach in clinical investigation of EEG signals. It was helpful to further understand the cerebral mechanism in schizophrenic cognitive process.

[A comparative study of N400 in generalized anxiety disorder versus obsessive compulsive disorder patients].

OBJECTIVE: To explore the features of events-related potentials (ERP) component N400 in generalized anxiety disorder (GAD) versus obsessive compulsive disorder (OCD) patients and understand the cognitive pattern and processing characteristic for Chinese characters. METHODS: ERP component N400 was recorded by Guangzhou Runjie WJ-1 ERP apparatus. And 41 GAD patients, 69 OCD patients and 58 normal controls (NC) were tested by the Chinese idioms ending with matching (congruent) or mismatching (incongruent) words. RESULTS: (1) Latencies: Significant differences were found of N400 latencies in ending words with the same pronunciation but different forms and meanings (NC: (377 ± 40) ms, OCD: (395 ± 43) ms, GAD: (396 ± 43) ms, congruent; NC: (415 ± 32) ms, OCD: (429 ± 35) ms, GAD: (430 ± 36) ms, incongruent), ending words with the same meaning but different pronunciations and forms (NC: (411 ± 32) ms, OCD: (424 ± 40) ms, GAD: (433 ± 39) ms, incongruent), ending words with different pronunciations, forms and meanings (NC: (399 ± 47) ms, OCD: (427 ± 53) ms, GAD: (434 ± 42) ms, congruent; NC: (442 ± 36) ms, OCD: (465 ± 35) ms, GAD: (474 ± 35) ms, incongruent) (P < 0.05 - 0.01). Compared with NC, the N400 latencies were prolonged in GAD and OCD patients. Compared with OCD patients, the GAD patients also showed prolonged N400 latencies in ending words with different pronunciations, forms and meanings (incongruent situation). (2) Significant differences were found of N400 amplitudes in ending words with the same pronunciation but different forms and meanings (NC: (9 ± 5) µV, OCD: (6 ± 5) µV, GAD: (6 ± 5) µV, congruent; NC: (11 ± 6) µV, OCD: (5 ± 4) µV, GAD: (6 ± 4) µV, incongruent), ending words with similar forms but different pronunciations and meanings (NC: (9 ± 5) µV, OCD: (5 ± 4) µV, GAD: (7 ± 5) µV, congruent; NC: (14 ± 6) µV, OCD: (6 ± 5) µV, GAD: (9 ± 7) µV, incongruent), ending words with different pronunciations, forms and meanings (NC: (9 ± 5) µV, OCD: (5 ± 4) µV, GAD: (5 ± 3) µV, congruent; NC: (14 ± 6) µV, OCD: (9 ± 7) µV, GAD: (9 ± 7) µV, incongruent) (P < 0.05 - 0.01). Compared with NC, N400 amplitudes decreased in GAD and OCD patients respectively. Compared with OCD patients, the GAD patients also showed elevated N400 amplitudes in ending words with similar forms but different pronunciations and meanings (congruent). CONCLUSION: The cognitive and emotional problems in GAD and OCD may be measured by N400 elicited by Chinese idioms. Notable N400 priming effects can be found in Chinese idioms.

Neonatal ventral hippocampal lesion as a valid model of schizophrenia: evidence from sensory gating study.

BACKGROUND: The neonatal ventral hippocampal lesion (NVHL) rat model has been proposed as an experimental model for schizophrenia. NVHL rats display impaired central nervous system (CNS) inhibition, which may lead to a phenomenon similar to P50 sensory gating deficits observed in schizophrenic patients. In this study, we investigated whether sensory gating deficits occurred in the NVHL rat as a model for schizophrenia. METHODS: We created the NVHL rat model using ibotenate. The P20 and N40 were measured to assess sensory response and gating in NVHL and sham rats. Epidural electrodes recorded evoked potentials (EPs), from which latencies, amplitudes, difference scores (S1-S2), and gating ratios (S2/S1) were assessed. RESULTS: Compared with sham controls, prolonged S1 N40 latency and decreased S2 N40 amplitude were detected in the NVHL group. In neither difference scores nor gating ratios, a significant difference was found between NVHL group and sham controls. CONCLUSIONS: NVHL rats may be a valid animal model for schizophrenia. This strategy will be useful in future neurobiological studies investigating the etiology of schizophrenia.

Differential sensory gating functions between smokers and non-smokers among drug-naive first episode schizophrenic patients.

Although an acute effect of cigarette smoking and nicotine on sensory gating of schizophrenias has been investigated in published papers, the chronic effect of cigarette smoking on this phenomenon has not yet been reported. We report the effects of chronic cigarette smoking, without new acute exposure before testing, on sensory gating using the P50 auditory evoked potential in a group of drug-naive first episode schizophrenic smokers and healthy smokers. Sensory gating was evaluated using auditory P50 suppression elicited using the conditioning (S1)-testing (S2) paradigm. Fifty six male drug-naive first episode schizophrenic patients were compared to 41 healthy male controls. Patients were classified into subgroups of current smokers (n=18) and non-smokers (n=38) to explore the effects of smoking on sensory gating. All subjects did not smoke a cigarette for at least 1h prior to testing. Schizophrenic patients showed an increased S2 amplitude and a poorer sensory gating as measured by both S2/S1 ratio and S1-S2 difference of P50 amplitude, as compared to healthy controls. However, smokers showed an increased S1 amplitude and better sensory gating than did non-smokers both in schizophrenia patients and healthy controls. Our findings support a sensory gating deficit among first episode schizophrenic patients. However, it was less pronounced among schizophrenic patients who were current cigarette smokers, suggesting a positive effect of chronic cigarette smoking on ameliorating this sensory gating deficit in schizophrenia. Our findings of the present study present new evidence supporting the self-medication hypothesis of self-medication by cigarette smoking in schizophrenia to possibly ameliorate pre-existing functional deficits.

[Preliminary study on variations and neural generators of error-related negativity in first episode schizophrenics].

OBJECTIVE: To explore the variations and their activated brain areas of error-related negativity (ERN) in first episode schizophrenics. METHODS: ERN was tested by an ERP device and their activated brain areas were compared in 58 first episode schizophrenics (FES) and 62 normal controls (NC) from March 2010 to February 2011. RESULTS: (1) The ERN latencies in the FES group were significantly longer on Cz (58 ± 14 ms), Fz (60 ± 11 ms), C3 (57 ± 17 ms) and C4 (60 ± 13 ms) electrodes compared with those in the NC group (49 ± 13 ms, 47 ± 13 ms, 50 ± 14 ms, 51 ± 12 ms). And the ERN amplitudes were significantly lower than those in the controls in Cz (5.0 ± 2.8 µV; 7.5 ± 3.1 µV, P < 0.01), C3 (5.5 ± 4.0 µV; 8.0 ± 3.7 µV, P < 0.01), Fz (5.0 ± 3.1 µV; 7.7 ± 3.8 µV, P < 0.01) and Pz (4.5 ± 3.3 µV: 7.5 ± 3.0 µV, P < 0.01) electrodes.(2) The variations of ERN latencies and amplitudes showed an insignificant correlation with the positive symptom scores and total scores of PANSS. (3) The activation levels of insula, superior temporal gyrus, middle temporal gyrus and inferior parietal lobule were obviously lower in the FES group than those in the NC group. CONCLUSION: The anomalies of ERN latencies and amplitudes in first episode schizophrenics may reflect the deficient error-monitoring functions. Further studies are warranted. And such brain areas as insular may contribute pathogenically to the dysfunctions of error-monitoring in schizophrenics.

[N400 changes elicited by Chinese sentences in first episode schizophrenia].

OBJECTIVE: To explore N400 changes elicited by Chinese sentences ending with matching (congruent) or mismatching (incongruent) words in first episode schizophrenia. METHODS: ERP (event-related potentials) component N400 were recorded by an ERP device in 56 first episode schizophrenia (FES) and 62 normal controls (NC) according to a paradigm of Chinese sentences ending with matching or mismatching words. RESULTS: (1) Latencies: compared with NC, FES showed prolonged N400 latencies in five areas at pre-treatment: in Cz. The latencies were (358 ms ± 32 ms vs 394 ms ± 45 ms, P < 0.01) in congruent and (410 ms ± 29 ms vs 446 ms ± 35 ms, P < 0.01) in incongruent situation. And so did in Fz, Pz, C3 and C4; (2) amplitudes: compared with NC, FES also showed smaller N400 amplitudes in five areas at pre-treatment. The amplitudes were (8.6 µV ± 5.1 µV vs 5.2 µV ± 4.6 µV, P < 0.01) in congruent and (13.4 µV ± 6.7 µV vs 8.5 µV ± 5.9 µV, P < 0.01) in incongruent situation. And so did in Fz, Pz, C3 and C4; (3) the prolonged N400 latencies and decreased amplitudes were negatively correlated with the patients' positive scale and total scale of PANSS. CONCLUSION: With clear priming effect in first episode schizophrenia, Chinese sentences are suitable stimuli in N400 experiment. They may be used for further study of neural mechanism and early diagnosis of schizophrenia.

[The follow-up study on P50 auditory sensory gating in naïve schizophrenia].

OBJECTIVE: To understand the variations of sensory gating P50 in naïve schizophrenia during follow-up and the relations with positive and negative symptom scale (PANSS). METHODS: The data of auditory evoked potential P50 were recorded by USA Nicolet Brova instrument from 58 naïve schizophrenia patients (Sch) and 108 normal controls (NC) at baseline, Months 1, 2 and 3 after treatment. And a simultaneous assessment of PANSS was made. RESULTS: (1) At baseline, as compared with NC, Sch group had a sensory gating deficit, reflected by a higher S2/S1 (Cz: NC: 0.43 (0.27, 0.58); Sch: 0.77 (0.58, 1.04); Z = -9.23, P < 0.01), lower S1-S2 (Cz: NC: 2.65 (1.55, 4.79) microV; Sch: 0.92(-0.13, 2.32) microV; Z = -6.01, P < 0.01) and decreased more (1-S2/S1) (Cz: NC: 0.57 (0.43, 0.73); Sch: 0.23 (-0.04, 0.42); Z = -10.61, P < 0.01). (2) During follow-up, Sch group still had a sensory gating deficit. Compared with NC, Sch group had a more elevated S2-P50 amplitude, higher S2/S1, lower S1-S2 and (1-S2/S1) at Cz, Fz and Pz brain sites (P < 0.05 - 0.01), and no significantly differences with S2-P50 amplitude, S2/S1, S1-S2 and (1-S2/S1) during follow-up (P > 0.05). At baseline, Sch group had a much lowered S1-P50 amplitude than NC group at Cz and Fz brain sites (Cz: Sch: 4.1 microV +/- 2.1 microV, NC: 5.6 microV +/- 3.3 microV, t = -1.47, P = 0.001; Fz: Sch: 3.9 microV +/- 2.1 microV, NC: 5.6 microV +/- 3.9 microV, t = -1.63, P = 0.003). At Month 3, Sch group showed an improved S1-P50 amplitude to normal level at Cz brain site, but S1-P50 amplitude improved at Fz brain site but it was lower than NC group (Sch: 3.9 microV +/- 1.9 microV, NC: 5.6 microV +/- 3.9 microV, t = -1.62, P = 0.03). (3) At Month 3, Sch group showed a much lowered PANSS scale, positive symptom scale, negative symptom scale and general psychiatric symptoms scale than that at baseline (baseline: 138 +/- 15, 33 +/- 7, 41 +/- 5, 65 +/- 8; Month 3: 80 +/- 15, 17 +/- 4, 24 +/- 4, 38 +/- 9 respectively, P < 0.01). Spearman correlation revealed that P50 was not correlated with PANSS at baseline (P > 0.05). After treatment S2/S1 and (1-S2/S1) correlated with positive symptom scale and thought disorder and S1-S2 positively with thought disorder in schizophrenia (P < 0.05). CONCLUSION: Sensory gating deficit is closely related with thought disorder in naïve schizophrenia. And it may be an important pathogenesis of naïve schizophrenia. P50 sensory gating deficit is probably a diathesis marker in schizophrenia.

[Experimental study on sensory gating in generalized anxiety and obsessive compulsive disorders].

OBJECTIVE: To observe the characteristics of sensory gating P50 in generalized anxiety disorder (GAD) and in obsessive compulsive disorder (OCD) patients. METHODS: Auditory evoked potentials P50 were recorded in 41 GAD patients, 69 OCD patients and in 58 normal controls by the conditioning/testing paradigm presented with auditory double clicks stimuli, using American Nicolet Bravo instrument. RESULTS: (1) No significant differences was found in latencies of S1-P50 and S2-P50 among these three groups (P > 0.05). (2) Significant differences were found in indices of S1-P50 amplitudes (NC: 6 +/- 3, GAD: 3 +/- 2, OCD: 5 +/- 3, P < 0.01), S2-P50 amplitudes (NC: 2 +/- 1, GAD: 4 +/- 1, OCD: 2 +/- 1, P < 0.01), S2/S1, S1-S2 and 100(1-S2/S1). (3) Compared with NC, GAD and OCD patients showed a decreased S1-P50 amplitude and OCD patients also showed an increased S2-P50 amplitude. (4) P50 inhibition significantly decreased in GAD and OCD patients. The values of S2/S1 ratio were 39% +/- 22% in NC, 50% +/- 29% in GAD and 88% +/- 42% in OCD (P < 0.01). (5) Both S1-S2 and 100 (1-S2/S1) decreased in GAD and OCD patients (NC: 3 +/- 2, 61 +/- 22; OCD: 1 +/- 1, 15 +/- 22; GAD: 3 +/- 3, 50 +/- 29. P < 0.01). (6) Compared with GAD, OCD patients showed a lower S2/S1 ratio (P < 0.01) and a higher value of S1-S2 (P < 0.01) and 100 (1-S2/S1) (P < 0.01). CONCLUSION: The anxiety disorder patients has sensory gating deficits. The inhibition deficit can be measured by auditory evoked potential P50. And S2/S1 ratio, S1-S2 and 100(1-S2/S1) may be biological markers of GAD and OCD patients.

N400 elicited by incongruent ending words of Chinese idioms in healthy adults.

BACKGROUND: Prior research about N400 has been mainly based on English stimuli, while the cognitive processing of Chinese characters is still unclear. The aim of the present study was to further investigate the semantic processing of Chinese idioms. METHODS: Event related potentials (ERP) component N400 was elicited by 38 pairs of matching (congruent) and mismatching (incongruent) ended Chinese idioms: ending words with same phoneme but different shape and meaning (sPdSdM), with similar shape but different phoneme and meaning (sSdPdM), with same meaning but different phoneme and shape (sMdPdS), and words with different phoneme, shape and meaning (dPdSdM) and recorded by Guangzhou Runjie WJ-1 ERP instruments. In 62 right-handed healthy adults (age 19 - 50 years), N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz, Cz and Pz. RESULTS: N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz. The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending words in healthy adults. Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-words idioms in healthy adults (P < 0.05). Compared with matching ending-words idioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones. N400s elicited by different types of stimuli showed different latencies and amplitudes, and longest N400 latency and largest N400 amplitude were elicited by ending-words with dPdSdM. No gender difference was found of N400 latency and amplitude in this study (P > 0.05). CONCLUSIONS: Compared with English stimuli, Chinese ideographic words could provide more flexible stimuli for N400 research in that the words have 3-dimension changes - phoneme, shape and meaning. Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the word. Some issues of N400 elicited by Chinese characters deserve further research.

A follow-up study on features of sensory gating P50 in treatment-resistant depression patients.

BACKGROUND: Depressive disorder is a well-known chronic, recurrent and disabling mental disease with high direct and indirect costs to society in both western and eastern cultures. Approximately 40% of depressed patients show only partial or no response to initial or even multiple antidepressant medications and are usually called treatment-resistant depression (TRD) patients. The present work was to measure the features of sensory gating (SG) P50 in TRD patients with the intent of understanding the characteristics of this disease. METHODS: In 50 TRD patients, 39 non-treatment-resistant depression (NTRD) patients and 51 healthy controls (HC), auditory evoked potential P50 was measured using the conditioning/testing paradigm presented with auditory double clicks stimuli, and 36 TRD patients had repeated measurements after an 8-week venlafaxine treatment course. RESULTS: All the depressive disorder patients, including the TRD and NTRD groups, showed an increased testing stimulus wave (S2-P50) amplitude compared to controls (P < 0.01 and P < 0.05), but there was no significant difference between the TRD and NTRD groups (P > 0.05). There were significant differences in the ratio of testing stimulus (S2) and conditioning stimulus (S1) (S2/S1) and in the value of 100 x (1 - S2/S1) among the three groups. Compared to the baseline, TRD patients had no significant changes of features and different expression of P50 after acute treatment (P > 0.05). Meanwhile, a statistically significant positive correlation of S2/S1 with the scores of the 17-item Hamilton Rating Scale for Depression (HAMD-17) (P < 0.01), and a significantly negative correlation of S1 - S2, 100 x (1 - S2/S1) with the scores of HAMD-17 (P < 0.01) were observed in the TRD patients' baseline measurement, but there was no correlation after venlafaxine treatment (P > 0.05). CONCLUSIONS: Both the TRD and NTRD patients had obvious SG deficits, with a more severe deficit in TRD patients. Although, with a correlated relationship to the severity of depressive symptoms, SG P50 deficit might be suggested as a trait marker for TRD, and a combination of S2/S1 ratio, S1 - S2 and 100 x (1 - S2/S1), was recommended for electrophysiological measurement in TRD patients.

[Effects of risperidone on polysomnography in patients with first-episode schizophrenia].

OBJECTIVE: To investigate the effects of risperidone on the polysomnography (PSG) in the patients with first-episode schizophrenia. METHODS: Twenty-five patients with first-episode schizophrenia, 13 males and 12 females, aged 29 +/- 8, underwent polysomnographic recording for 4 consecutive nights, the first night being used for acclimatization, and on the 3 rd and 4 th nights risperidone in the dose of 1.2 mg was administered before going to bed. Forty-four healthy persons, 23 males and 21 females, aged 28 +/- 8, underwent polysomnographic recording for 2 consecutive nights, the first night being used for acclimatization. RESULTS: The baseline PSG recording showed that in comparison with the normal control group the total sleep time of the schizophrenia patients was shorter (378 min +/- 30 min vs 462 min +/- 21 min), sleep latency was longer (30 min +/- 14 min vs 18 min +/- 8 min), rapid eye movement (REM) sleep latency was shorter (59 min +/- 20 min vs 88 min +/- 10 min), REM sleep time was shorter (61 min +/- 17 min vs 84 min +/- 12 min), awakening time was longer (34 min +/- 17 min vs 15 min +/- 5 min), stage 1 (S1) time was longer (22% +/- 10% vs 9.0% +/- 1.7%), S3 time and S4 time were shorter, and the sleep efficacy was lower (86% +/- 10%) (P < 0.05 approximately P < 0.01); however, there was no significant difference in the S2 time between these 2 groups (54% +/- 16% vs 56% +/- 4%, P > 0.05). In the schizophrenia group, in comparison with the baseline levels in the third and fourth nights the total sleep times were significantly increased (406 min +/- 34 min and 428 min +/- 31 min respectively), the awakening times were significantly decreased (23 min +/- 15 min and 19 min +/- 8 min respectively), and S1 times were significantly decreased (14 min +/- 9 min and 10 min +/- 9 min respectively), with such changes time-dependently; and in the 4 th night the REM sleep time was significantly increased (87 min +/- 20 min) and the sleep efficacy was significantly improved (93% +/- 12%) (P < 0.05 approximately P < 0.01), however, there were no significant differences in the sleep latency and slow wave sleep (both P > 0.05). CONCLUSION: Risperidone significantly improves the quality of sleep.

[Sensory gating of patients with first-episode schizophrenia].

OBJECTIVE: To investigate the characteristics of sensory gating P50 of patients with first-episode schizophrenia. METHODS: The auditory evoked potentials P50 were recorded in 66 patients (Group Sch) with first-episode schizophrenia and 92 normal controls (Group NC) by using conditioning/testing paradigm presented with auditory double click stimuli. RESULTS: The value of S1-P50 of Group Sch was 3 microV +/- 2 microV, significantly lower than that of Group NC (6 microV +/- 3 microV, P <0.01). The value of S2-P50 of Group Sch was 4 microV +/- 2 microV, significantly higher than that of Group NC (2 microV +/- 1 microV, P < 0.01). The S2/S1 ratio of Group Sc was 81% +/- 40%, significantly higher than that of Group NC (42% +/- 21%, P < 0.01). The value of S2 - S1 of Group Sch was 2 microV +/- 1 mciroV, significantly lower than that of Group Sch (3 mciroV +/- 2 microV). The value of 100 (1-S2/S1) of Group Sch was 19% +/- 17%, significantly lower than that of Group NC (58% +/- 21% , P < 0.01). CONCLUSION: Sensory gating deficit exists in the patients with first-episode schizophrenia, manifested in deficiency of inhibition that can be quantitatively observed by measuring auditory evoked potential P50.