Previous research has shown that mental illness can affect auditory processing and speech understanding, but is that true even when a person is not experiencing symptoms? A study published in The Journal of Neuropsychiatry and Clinical Neurosciences suggests that people with mood disorders have impaired speech understanding, even when in remission.
Mental and neurological disorders can have profound effects on a myriad of varying aspects of the lives of people struggling with them. One effect that has been increasingly studied in recent years is the relationship between auditory processing and several mental illnesses, including schizophrenia, depression, and alcohol addiction.
A relationship that is currently understudied is how speech understanding may be affected by mental illness. Speech understanding involves auditory processing, but also visual, motor, and other cognitive functioning. The new study sought to bridge this gap in the literature by exploring understanding of speech in noise for people with bipolar disorder or depression, both in remission and during a mood episode.
For their study, Maria Napierata and colleagues utilized 43 patients with bipolar disorder, 32 patients with unipolar depression, and 35 control participants to serve as their sample. Of the 43 patients with bipolar disorder, 20 had manic and 23 had depressive. Mood disordered participants were recruited from a hospital and healthy controls volunteered.
Participants completed the the Polish Sentence Matrix Test to measure speech recognition in noise and an audiological evaluation. Measures were completed twice, once when in the course of a manic or depressive episode and once when in remission.
The Polish Sentence Matrix Test is used to measure how well someone can understand speech when there is background noise. The test calculates the Speech Reception Threshold (SRT), which is the minimum volume needed to understand 50% of the spoken words, measured in decibels. The audiological evaluation assessed the function of the middle ear and hearing sensitivity at different frequencies from low to high ranges.
The results showed that both bipolar disorder and unipolar depression were associated with worsened speech understanding compared to the control subjects, whether they were symptomatic or in remission. For participants with bipolar disorder, being in remission yielded similar levels of speech understanding as being actively in a manic episode.
For depression, in both patients with bipolar disorder and unipolar depression, being in a depressive episode led to lower speech understanding than being in remission. There were no significant differences in speech understanding between participants with bipolar disorder and participants with unipolar depression. In unipolar depression, poor
speech understanding was more severe in individuals with hearing impairment.
“This has practical implications because speech perception in typical social conditions is often disturbed by noise, leading to communication problems, and may exacerbate social difficulties for patients with mood disorders,” the researchers wrote.
This study took important steps into better understanding how mood disorders affect the ability to understand speech. Despite this, there are limitations to note. One such limitation is that the general cognition of subjects was not measured, so one cannot definitively determine that these results were due to mood disorder, rather than cognitive ability. Additionally, all mood disordered patients were receiving pharmacological intervention, which could affect results.
The study, “Speech Understanding in Manic and Depressive Episodes of Mood Disorders“, was authored by Maria Napierała, Aleksandra Suwalska, Beata Pucher, and Janusz K. Rybakowski.