Event-related potentials and white matter lesions in bipolar disorder

The P300 event-related potential in bipolar disorder: A systematic review and meta-analysis

BACKGROUND

Neurophysiology including P300, that is a typical index of event-related potential, may be potential biomarkers for bipolar disorder (BD) and it can be useful towards elucidating the pathophysiology of BD. However, previous findings from P300 studies were inconsistent due to the heterogeneity of research methods, which make it difficult to understand the neurobiological significance of them. The aim of this study is to conduct a meta-analysis on P300 in patients with BD.

METHOD

A literature search was conducted using PubMed to identify studies that compared P300 event-related potential between patients with BD and healthy controls (HCs). We analyzed P300 indices such as amplitude and latency of P3a and P3b in auditory or visual paradigms. Further, moderator analyses were conducted to investigate the influence of patient characteristics (i.e. history of psychosis, diagnostic subcategories [BD-I/BD-II], and phase of illness [euthymic, manic, or depressive]) on P300 indices.

RESULT

Out of 124 initial records, we included 30 articles (BD: N = 1331; HCs: N = 1818). Patients with BD showed reduced P3a and P3b amplitude in both paradigms and delayed P3b latency in auditory paradigms compared to HCs. There was no influence on the history of psychosis, diagnostic subcategories, or phase of illness on P300 indices.

LIMITATION

The difference in medication use was difficult to control and it may affect the results.

CONCLUSION

This meta-analysis provides evidence for P300 abnormalities in patients with BD compared to HCs. Our results suggest that P300 may be trait markers rather than state markers in this illness.

Evaluation of event-related potentials in Klinefelter syndrome and idiopathic hypogonadotrophic hypogonadism

BACKGROUND

Many studies have evaluated patients with idiopathic hypogonadothropic hypogonadotropism (IHH), but few of these studies utilize event-related potentials (P300).

AIMS

To assess the cognitive functions of hypergonadotropic vs. hypogonadotropic patients.

SETTINGS AND DESIGN

The study group consisted of 41 untreated IHH patients, 32 untreated Klinefelter syndrome (KS) patients, and 30 healthy control subjects.

METHODS AND MATERIAL

In this study, the latency and amplitude of P300 was evaluated in 41 untreated IHH and 32 untreated KS patients and compared to healthy control subjects (average age: 30 years). Also evaluated were the patients' hormone levels.

RESULTS AND CONCLUSIONS

In this study, the amplitude of P300 was found to be reduced, and the latency prolonged in IHH patients in comparison to KS patients and control subjects. In KS patients, there was no difference in latency of P300, but the amplitude was reduced when compared with the control group. Cognitive dysfunction in patients with hypogonadotropism is related to androgen hormone levels. This deficiency can affect development of the central nervous system (CNS), causing defects of CNS to varying degrees during the perinatal period. Androgen deficiency is considered to exert its effects during the period of cognitive ability development, manifest in IHH patients but not KS patients.