Table 1 Studies included in systematic review

Matsuo, J. et al. 2018 [35]

To assess PPI deficits in patients with BD stratified by gender and disease status (euthymic/depressed).

106 BD (63 with depression and 43 euthymic; 26 BD I and 80 BD II) and 232 control subjects.

All individuals were evaluated using the computerized startle reflex test unit, lead

Interval of prepulse-pulse is 60 ms and 120 ms.

The male BD patients with depression had significant PPI deficits, female BD patients with psychosis show lower PPI.

qualitative synthesis

QJ, Bo. et al. 2018 [36]

Using a perceived PSS-PPI paradigm to assess PPI levels in patients with BD.

30 non-manic patients with BD and 33 HC

PPI was evaluated using a modified PSS-PPI paradigm, lead Interval of prepulse-pulse is 120 ms

Patients with BD exhibited PPI deficit by using PSS-PPI paradigm. PSS-PPI deficits was significantly associated with the language domain of RBANS.

qualitative synthesis

Sanchez-Morla, E. M. et al. 2016 [16]

To assess PPI level in euthymic patients with BD.

64 euthymic patients with BD and 64 control subjects

The acoustic startle measures of PPI were performed using 60-ms and 120-ms lead interval.

Compared with HC, BD patients showed PPI deficits that is related to social cognition

qualitative/quantitative synthesis

Tamminga, C. A. et al. 2014 [37]

To assess SPEM, PPI, and ERP between schizophrenia and BD

26 psychotic bipolar I disorder and 22 HC were tested for PPI level.

Standard clinical characterization and PPI (lead Interval, 120 ms) paradigm were applied.

PPI level did not differ between psychotic bipolar I disorder and HC.

qualitative synthesis

Gogos, A. et al. 2009 [26]

To explore gender difference in PPI level in patients with BD.

29 euthymic patients with BD, and 32 HC.

Two PPI stimulus onset asynchrony levels (60, 120 ms) were assessed by 21 pulse-alone trials (115 dB) and a total of 42 prepulse-pulse trials.

Compared with controls, the male patients with BD showed reduced PPI, whereas female patients had increased PPI levels.

qualitative/quantitative synthesis

Carroll, C. A. et al. 2007 [29]

To assess PPI level in manic and mixed episode BD.

14 manic patients with BD, 21 mixed episode patients with BD and 32 HC.

The acoustic startle measures of PPI were performed using a 120-ms lead interval.

Compared to HC, mixed episode patients exhibited less PPI latency facilitation, but PPI deficits were not observed across diagnostic groups (manic, mixed, control)

qualitative synthesis

Giakoumaki, S. G. et al. 2007 [20]

To assess PPI level in remitted patients with BD and their unaffected siblings.

21 patients with BD, 19 unaffected siblings and 17 HC

The tests of acoustic startle reactivity and PPI (lead Interval, 60 ms and 120 ms) of the startle response were investigated.

Patients with BD and their unaffected siblings showed PPI deficits, and had no significant correlation with symptom and disease severity.

qualitative/quantitative synthesis

Barrett, S. L. et al. 2005 [28]

To assess PPI level in the euthymic phase of BD.

23 euthymic patients with BD, and 20 HC.

The tests of acoustic startle reactivity and PPI of the startle response were performed. Lead interval of prepulse-pulse is 60 ms and 120 ms

There was no significant PPI deficits in the euthymic phase of BD.

qualitative/quantitative synthesis

Rich, B. A. et al. 2005 [30]

To investigate PPI level in pediatric BD.

16 patients with BD (medicated, euthymic and nonpsychotic), and 13 HC.

The magnitude of startle habituation, startle-alone response, and inhibition of startle following a 60 or 120-ms prepulse were evaluated.

Pediatric BD patients did not show PPI deficits compared to healthy controls.

qualitative/quantitative synthesis

Braff, D. L. et al. 2001 [27]

To explore PPI level in BD patients with acute psychotic mania.

15 patients with BD, 16 patients with schizophrenia and 17 HC

PPI (60 ms and 120 ms interstimulus intervals) was measured using Xeye Human startle reflex system.

Compared with HC, BD patients with acute psychotic mania had PPI deficits, and the extent of deficits was not significantly different from schizophrenia

qualitative synthesis