Available online 2 April 2024, 111813

Author links open overlay panel, , , , , HIGHLIGHTS•

Sensory gating was examined with ERPs in MDD patients and healthy volunteers.

•

In a paired-stimulus (S1-S2) paradigm patients exhibited reduced P50 gating.

•

Patients showed reduced gating, larger S2-P50 amplitudes and slower N100 latencies.

•

Aberrant gating and S2-P50 correlated with increased depression and hopelessness.

•

N100 slowing correlated with increased hopelessness and dysfunctional attitudes.

ABSTRACT

Cognitive deficits in depression are pervasive and include impairments in attention and higher-order functions but the degree to which low-level sensory processes are affected is unclear. The present work examined event-related potential (P50 and N100) features of auditory sensory gating (i.e., the ability to inhibit P50/N100 responses to redundant stimuli) and their relationship to depressive symptoms, including ruminations and dysfunctional attitudes. In 18 patients with major depressive disorder (MDD) and 18 healthy volunteers, auditory sensory gating was measured using a paired-stimulus paradigm yielding ratio (rP50, rN100) and difference (dP50, dN100) gating indices, which reflected amplitude reductions from first (S1) to second (S2) stimulus. Patients with MDD exhibited diminished rP50 and dP50 gating scores and delayed S1-N100 latencies compared to healthy volunteers. These measures were positively associated with ruminative thoughts, negative attitudes and degree of depression. Study findings implicate aberrant sensory processing in depressed patients that is related to severity of maladaptive thinking.

Section snippetsINTRODUCTION

Top-down approaches elucidating the etiology and maintenance of depression have emphasized the contributory role of cognitive impairments resulting from aberrant activity in fronto-limbic cortical circuitry. Although not specific to depression and exhibited at only small to medium effect sizes, cognitive deficits in major depressive disorder (MDD) are consistent, replicable, and clinically significant and account for the largest percentage of variance with respect to the link between

Experimental Participants

A sample of 18 individuals were drawn from an outpatient clinical trial conducted at the Royal Ottawa Mental Health Centre's (ROMHC) Mood Disorders Unit. The aim of the trial was to compare the efficacy of intensive pharmacotherapy interventions (IPI: initiating two antidepressant medications at treatment onset) to standard tertiary care services. Patients were either medicated or not at the start of the trial (medicated individuals would either be switched to a different medication, or a dose

RESULTS

The matched patients and healthy control groups both consisted of 13 female and 5 male participants. The mean ages (±standard deviations) and medication status/comorbidities (patient group only) at the time of testing are presented in Table 1. We did not collect data on education level, which has been previously shown to be related to ERP indices of sensory gating (Lijffijt et al., 2009a). The average MADRS score of the patient group was 29.4 (± 1.2), indicating moderate depression. As shown in

DISCUSSION

There are a number of limitations to our study which include relatively small sample sizes and possible confounding effects of medication and comorbid diagnoses. We also did not examine the potential role of education level, which has been related to gating indices in earlier work (Lijffijt et al., 2009a). It is within this context that we observed our main study findings that patients with a depressive disorder exhibited a P50 sensory gating deficit compared with healthy volunteers. Also, this

Uncited References

Boutros et al., 2009, Engel-Yeger, 2011, Engel-Yeger et al., 2018, Montgomery and Asberg, 1979, Serafini et al., 2017

CRediT authorship contribution statement

Sara de la Salle: Writing – review & editing, Writing – original draft, Visualization, Validation, Supervision, Software, Project administration, Methodology, Investigation, Formal analysis, Data curation. Hayley Bowers: Writing – review & editing, Writing – original draft, Project administration, Investigation. Meagan Birmingham: Writing – review & editing, Writing – original draft, Supervision, Project administration, Investigation. Jennifer L. Phillips: Writing – review & editing, Writing –

Declaration of competing interest

Dr. P. Blier was in receipt of a Tier 1 Canada Research Chair and an Endowed Chair from the Royal's Institute of Mental Health Research (IMHR) and has received research support or speaker honoraria from or served as a consultant to, Allergan, Bristol-Myers Squibb, Janssen, Lundbeck, Otsuka, Pierre Fabre Médicaments, Pfizer, Shire, and Takeda. The other authors have no other not conflicts of interest to disclose.

Acknowledgment

The clinical trial aspect of this work was supported by a grant from Great West Life and a Canadian Institutes of Health (CIHR) Project grant (274324; PI: Dr. P. Blier)

View full text

© 2024 Published by Elsevier B.V.