Evaluation of cognitive impairment in schizophrenia
Zhang Xing's Ji Jun
Guo Zhang Mingyuan
Objective To explore the different characteristics of P300 between Alzheimer's disease and senile schizophrenia. Methods 39 AD patients, 34 SS patients and 40 normal elderly people who met DSM-III-R III-R diagnostic criteria were collected. P300 was detected by Danish instrument, with "auditory target-non-target stimulation sequence" as the trigger event. Results In AD group, P300 waveform changed, and the latency N 1 of P300 target and non-target moved forward obviously. The average P3 amplitude of P300 main wave is 65.04% and 60% lower than that of SS group and normal control group, respectively. The target and non-target latencies N 1 and P2, and the target latencies N2 and P3 in SS group were significantly earlier than those in normal elderly group. The average target amplitude of P3 wave is 54% lower than that of normal elderly people. Although the latency of target P3 in AD group was delayed, the difference was not significant. Conclusion P300 can assist the cognitive function evaluation of AD patients and SS patients.
Keywords schizophrenia, Alzheimer's disease evoked potential, hearing
Evaluation of auditory P300 on cognitive dysfunction in Alzheimer's disease and schizophrenia * Zhang, Chen Xingshi, Lou, et al * Shanghai Institute of Mental Health, Shanghai 200030.
Objective To explore the value of auditory P300 in evaluating cognitive dysfunction in elderly patients with Alzheimer's disease (AD) and schizophrenia. Methods Using the "oddball" paradigm, 39 patients with Alzheimer's disease diagnosed by DSM-III-R, 34 elderly schizophrenics and 40 normal subjects were induced by auditory P300 with Dante Concerto Seeg-16 auditory evoked potentials. Results The variability of P300 waveform in AD patients increased, which showed that N 1 latency was shortened due to frequent stimulation. P3 amplitude of AD patients is 65.04% lower than that of schizophrenia patients and 60% lower than that of normal people. Compared with the normal control group, the latency of N 1, P2, N2 and P3 in schizophrenic patients was shortened, and P3 amplitude was reduced by 54%. Conclusion Auditory P300 is valuable for evaluating cognitive dysfunction in AD patients and elderly schizophrenics.
Keywords schizophrenia evoked potential of Alzheimer's disease, hearing,
(China National Journal of Medicine, 1998, 78:454-456)
In recent years, P300 detection technology has been widely used in clinical medicine [1]. In order to explore the difference of P300 between Alzheimer's disease (AD) and senile schizophrenia (SS), we recently tested P300 between the two groups.
Objects and methods
I. Objection
1.AD group: 39 cases, male 14, female 25. Patients were selected from Shanghai Mental Health Center (branch), aged 65-85 years, with an average of 74.65438 0.5 years. The course of disease ranged from 65438 0 months to 65438 0.5 years, with an average of 3.4 2.9 years. Years of education (ED)0 ~ 14, with an average of 5.0 5.2, and cognitive function screening scale (CASI)2 ~ 62, with an average of 27.615.9.
2.SS group: 34 cases, male 2 1 case, female 13 cases. The age ranged from 665438 0 to 87 years, with an average of 67.5 5.2 years. The course of disease was 65438 07 ~ 53 years, with an average of 33.7 8.6 years. Ed 0 ~ 16, with an average of 6.9 5.6; CASI 18 ~ 99, with an average of 55.3 29. 1.
According to DSM-ⅲ-R III-R criteria, two doctors were diagnosed as AD patients and SS patients respectively. There were no serious physical diseases in both groups, and both patients had undergone CT examination. AD group did not use acetylcholine related drugs for nearly 1 month and a half, and could cooperate to complete the experiment. Among 34 SS patients, 10 patients did not take psychotropic drugs, and 24 patients took antipsychotics (chlorpromazine, perphenazine, terden, trifluoperazine). In order to eliminate the influence of psychotropic drugs on P300, we first compared 24 patients who took chlorpromazine (the average daily dose was1571kloc-0/9 mg) with those who did not take chlorpromazine, and the statistical difference was not significant (P & gt0.05). Secondly, we have consulted the recent foreign literature, which is still controversial. Most people think that small and medium doses have little effect on brain waves [2]. This study preliminarily ruled out the interference of drugs on P300.
3. Normal control group: 40 cases, male 16, female 24; The age ranged from 63 to 86 years, with an average of 74.4 5.7 years. Ed 0 ~ 25, with an average of 9.7 4.7; CASI 59 ~ 99, with an average of 9 1.8-7.9. All subjects were healthy employees and community volunteers in our center. There was no obvious physical disease and dementia in the past, and there was no abnormality in CT examination of the head. There is no significant difference in age and sex among the above-mentioned AD group, SS group and NC group, but the education years of NC group are higher than those of the two disease groups.
Second, the method
Test instrument: Danish Dantec Concerto SEEG- 16 channel electrophysiology instrument. According to the standard of the International Electroencephalography Society 10/20, recording electrodes were placed in F3, F4, C3, C4, P3, P4, Fz, Cz and Pz, with the retroauricular mastoid r 1+R2 as the reference electrode, Fp grounded, and the inter-electrode impedance.
The whole experiment was conducted in a shielded room. Before P300 test, all subjects were examined for auditory brainstem response, and it was confirmed that clear ABR waveform could be elicited under 80 dB sound stimulation, and their hearing was normal.
Third, analysis
The instrument has the functions of automatically removing artifacts and resisting noise interference. All numerical values are automatically measured, calculated and displayed by digital cursor function. Indicators include: (1) fundamental wave type and its variation (late component of 50 ~ 700 ms). (2) Latency period (ms): the target indicators are N 1, P2, N2, P3; Non-target indicators are N 1 and P2. (3) Amplitude (μV): the target indexes are P2 and P3; The non-target indicator is P2.
4. Data processing: All data are input into a microcomputer, and variance analysis is performed with SPSS6.0 statistical software package.
result
1. Waveform analysis: P300 waveforms in AD group and SS group have variation, and the variation is greater than that in NC group. However, the AD group was significant, and the overall waveform differentiation was poor. The individual waveforms of SS group are also uneven. There was no significant difference in P300 principal components between AD group and SS group in Fz, Cz and Pz brain regions (P & gt0.05), which was consistent with the normal elderly. Compared with the left and right hemispheres of frontal lobe, the N 1 latency on the right side (F4) of AD group and SS group was longer than that on the left side (F3), with significant difference (P
2. Target stimulation: Compare the latency and amplitude of target stimulation in P300-Cz area among AD group, SS group and NC group (see table 1).
From the table 1, it can be seen that the latency (N 1, P2, N2, P3) and amplitude P2 and P3 of P300 target stimulation are significantly different among AD group, SS group and NC group (P
The standard deviation of P300 principal component in AD group is greater than that in SS group. The differences of target latency P2, N2 and P3 between AD group and SS group were significant or very significant (P < 0.05 or P
3. Non-target stimulation: Comparison of main indexes of latency and amplitude of non-target stimulation in P300-Cz area among AD group, SS group and NC group (see Table 2).
As can be seen from Table 2, the latency N 1 and P2 of P300 and the amplitude P2 of P300 in AD group, SS group and NC group are also significantly different by F test (P
Table1Comparison of P300-Cz Regional Indicators among Ad Group, SS Group and NC Group
The number of cases in target latency (ms) and target amplitude (μV) in group A.
N 1 P2 N2 P3 P2 P3
NC group 40 106 1 1.
184 2 1
250 22
330 28
5.2 2.3 6.3 2.8
Advertising Group 39 97 22 *
173 34
252 40
339 49
3. 1 2. 1** 2.5 1.9**
SS team 34 87 24 * *
143 35**
2 12 29**
286 32**
3.2 2.4** 2.9 2.2**
F value 8.897
17.068
18.853
20. 15
10.57 1 30.768
P value
& lt0.0 1
& lt0.0 1
& lt0.0 1
& lt0.0 1 & lt； 0.0 1
Note: Compared with NC group.
P300-Cz region in AD group, SS group and NC group.
Non-target index comparison
Number of cases in the group: non-target latency (ms) and non-target amplitude (μV)
N 1 P2 P2
NC group 40 105 23
189 47
3.6 1.8
Advertising group 39 9 1 17 * *
209 29*
2. 1 1.8**
SS group 34 9 1 20 * *
168 23*
2.2 1.4**
f 6.42 1. 1.07 1.9545
P value
Note: Compared with NC group, * p
Q test showed that the difference between NC group and NC group was significant or very significant (P < 0.05 or P
There was significant difference in non-target latency P2 between AD group and SS group (P
discuss
P300 of AD group, SS group and NC group were compared. The results showed that P300 waveform in AD group varied, and the latency of P300 target and non-target N 1 moved forward obviously. The average P3 amplitude of P300 main wave is 65.04% and 60% lower than that of SS group and normal control group, respectively. In SS group, the target and non-target latencies N 1 and P2, and the target latencies N2 and P3 all moved forward obviously. The average target amplitude of P3 wave is 54% lower than that of normal elderly people. Although the latency of target P3 in AD group was delayed, the difference was not significant.
Before this study, a single disease was reported in Europe and America [4 ~ 7]. Goodin first proposed P300 as the diagnostic index of AD. This discovery was reported in the late 1980s and early 1990s. The abnormal rate of P300 in AD patients was 13 ~ 83%. However, police [8] believes that this change is not obvious in the early stage of AD. There are few reports about P300 in SS patients, and the latency and amplitude of P300 in quite a few SS patients can be prolonged and decreased [1, 3,9, 10].
Some results in this paper are the same as those in the above literature. However, the P3 latency of AD patients was significantly prolonged, while that of SS patients was prolonged, and the amplitude of the three recording points in the midline was decreased, which could not be reproduced in this study group.
The difference between this work and European and American works is mainly in AD, which uses multiple recording points to obtain more information, and the left and right sides of the frontal lobe are asymmetrical (non-target N 1 latency). Whether these characteristics have universal significance needs further follow-up.
The P300 amplitude and left-right variation characteristics of AD group and SS group are similar, but the degree of abnormality in AD group is greater than that in SS group. However, it is easy to distinguish the two groups of diseases by latency and waveform trend, such as delayed latency and poor waveform differentiation in AD patients; However, the waveform of SS patients is bimodal, the latency is delayed, and some indexes move forward. We think that P300 in AD group and SS group is different from that in NC group, and there are obvious differences in abnormal manifestations between AD and SS, suggesting that P300 can still be used as a marker for auxiliary diagnosis or differential diagnosis of AD and SS patients. The endogenous components P3 and N2 of P300 in AD group were only slightly longer than those in NC group, and there was no significant difference. The reasons need to be further explored in the future.
With regard to the explanation of P300 changes in patients with AD and SS, the prolonged AD latency indicates that the patient's recognition speed and decision-making process of the target stimulus are slow, suggesting the failure of information processing function [4]. The decrease of P300 amplitude in some AD and SS patients is related to the atrophy of cerebral cortex and the decrease of the number of brain nerve cells involved in the reaction [1]. Through the above experiments, we initially think that P300 measurement has the advantages of no language, writing, action and other requirements, no cultural restrictions, easy acceptance by patients, short time and so on. And can quantitatively evaluate people's cognitive function, which is more suitable for the clinical application of geriatric psychiatry.
This topic is supported by the leading key discipline of geriatric psychiatry in Shanghai.
Author: 200030 Shanghai Institute of Mental Health (Zhang, Chen Xingshi, Lou,); Shanghai Second Medical University (Guo); Shanghai Mental Health Center (Zhang Mingyuan)
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(Received: 1997- 12-05 modified: 1998-04-02)
(Editor of this article: Yuan Guiqing)