Parkinson’s Disease (PD) is often associated with motor symptoms like tremors and stiffness. However, many individuals with PD also experience subtle but impactful language difficulties, even early in the disease. In particular, they may struggle to understand words related to actions—especially verbs like run, cut, or write—as well as nouns tied to physical interaction, like hammer or scissors.
These challenges can affect everyday communication and overall quality of life. Yet most speech-language therapies for PD focus primarily on improving speech production (like voice volume), rather than addressing language comprehension issues. A study supported by the Klein Family Parkinson’s Rehabilitation Center and led by Amy Lebkuecher, PhD, and Laurel Buxbaum, PsyD, in collaboration with Pippa Siguenza, MS, CCP, SLP, and Branch Coslett, MD, from the University of Pennsylvania is investigating whether observing meaningful gestures can support language comprehension in PD. Those who participated in the experiment completed a task in which they viewed short videos of gestures followed by spoken words. For some trials on the task, the gesture and word referred to the same concept (e.g., a cutting gesture followed by “scissors”), while in others, they were unrelated. Participants were asked to determine whether the gesture and word were related, allowing researchers to measure both accuracy and the time it takes to respond to each trial (i.e., response time).
Dr. Lebkuecher and colleagues are investigating whether gestures make comprehension faster and more accurate, and whether this differs between participants with PD and participants in the same age range without neurological conditions. They will also examine whether individual differences—such as the ability to recognize meaningful gestures—are related to individual differences in the extent to which gestures support language comprehension.
In addition to examining accuracy and response time differences, this study used electroencephalography (EEG) to investigate the brain activity associated with the relationship between gesture and language comprehension. Some theories of language comprehension argue that understanding language related to actions depends on simulating those actions in the same network of brain areas responsible for performing the actions. In other words, to understand the words “cutting” or “scissors,” these theories propose that your brain simulates the act of using scissors in the same brain regions that allow you to use scissors in real life. Supporters of these theories argue that disruptions of this network that occur in PD may lead to difficulty understanding language related to actions.
By examining both brain activity and behavior on the experimental task, the researchers aim to determine whether individuals in PD exhibit difficulties with language comprehension and if they are driven by disruptions in the network of brain areas responsible for performing actions. The data has been collected for this experiment and analyses are currently underway to examine the validity of these theories.
From a clinical perspective, the findings may help identify why language comprehension is affected in some individuals with PD and which of these individuals are most likely to benefit from incorporating gesture into speech-language therapy. More broadly, the results could inform the development of interventions that address not only motor speech difficulties but also language comprehension deficits, ultimately improving communication and quality of life for individuals with PD.
By bridging neuroscience, language science, and clinical practice, this research takes an important step toward more personalized and effective treatments for communication challenges in Parkinson’s disease.
And it reminds us of something fundamental: communication is not just about words—it’s about the whole body working together to create meaning.