Psychomotor retardation (PMR) is a set of symptoms involving the slowing of movement and thoughts. One aspect of motor activity that’s affected is speech, which is what this post will focus on. This interests me because PMR is the most treatment-resistant aspect of my depression, and speech impairment has had a significant impact on my overall ability to function.
Speaking involves both cognitive planning tasks and complex motor tasks. PMR can get in the way of both, and several neurological mechanisms have been suggested for this. I notice an impact on the cognitive elements of putting together words and word-finding, but what feels subjectively most difficult is what I wound describe as finding and implementing the motor scripts for words. It’s easier for me to say a multi-syllable word than having to say multiple short words of the same overall syllable length, as it feels like I need to retrieve each word one at a time.
PMR affects speech in a number of ways. Tone, Inflection, articulation, and volume are decreased, so speech is quiet, monotone, and less fluent. There are also more and longer pauses, which to me subjectively feels like having to retrieve words one at a time. Responses are delayed and of decreased length.
Speech changes and depression severity
Not everyone with depression, or even severe depression, exhibits psychomotor retardation. However, changes in speech can be indicative of depression severity. I had a hard time following the specifics in the papers I was looking at, because I don’t know anything about acoutistics or phonology, but it sounds like there are specific detectable differences that are relevant to severity.
In one study, objectively measured changes in speech, specifically speech rate, pause time, and response time, were partially correlated to severity scores on the HAM-D, a commonly used test for measuring depression severity.
Another study found that several acoustic features were associated with greater depression severity, including features indicative of decreased precision in motor control, as well as decreased variability in certain speech parameters.
While the two main rating scales used to assess PMR rely on a clinician’s subjective evaluation of a patient’s speech, there is technology that can objectively evaluate this. However, the challenge lies in figuring out what’s best to measure and being able to separate out the various other factors that can affect speech.
Acoustic measurements show similarities in the speech impairment seen in depression-related PMR and Parkinson’s disease, suggesting there may be similar pathways in the brain that are involved. The biology of PMR isn’t well-understood, but it does seem to involve dopamine activity in the basal ganglia region of the brain, which is also affected in Parkinson’s.
Changes in glottalization, an effect sometimes described as creaky voice, may be a result of changes in laryngeal muscle tension in the throat. Overall, it sounds like it’s very muscle control-based rather than being driven by cognitive changes.
This is depression?
Psychomotor retardation is a good example of how mental illness (in general, not just depression) isn’t just about what goes on wth thoughts and feelings; mental illness happens in the brain, and the brain is connected to the body. There’s a lot of room for variation under the diagnostic umbrella of depression, and one person’s depression make look and feel very different from another person’s.
What I find the most frustrating is that people hear me talk and, whether intentionally or not, assume that my speech impairment is reflective of cognitive impairment. The judginess pisses me off, and when I’m angry, I start to get shaky, which just makes my speech worse.
So yeah, depression is annoying.
- Buyukdura, J. S., McClintock, S. M., & Croarkin, P. E. (2011). Psychomotor retardation in depression: biological underpinnings, measurement, and treatment. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 35(2), 395-409.
- Flint, A. J., Black, S. E., Campbell-Taylor, I., Gailey, G. F., & Levinton, C. (1993). Abnormal speech articulation, psychomotor retardation, and subcortical dysfunction in major depression. Journal of Psychiatric Research, 27(3), 309-319.
- Quatieri, T. F., & Malyska, N. (2012). Vocal-source biomarkers for depression: A link to psychomotor activity. In Thirteenth Annual Conference of the International Speech Communication Association.
- Yamamoto, M., Takamiya, A., Sawada, K., Yoshimura, M., Kitazawa, M., Liang, K. C., … & Kishimoto, T. (2020). Using speech recognition technology to investigate the association between timing-related speech features and depression severity. PloS one, 15(9), e0238726.