Maresh, K., Papageorgiou, A., Ridout, D., Harrison, N. A., Mandy, W., Skuse, D., & Muntoni, F. (2023). Brain: a journal of neurology, 146(1), 252–265. https://doi.org/10.1093/brain/awac048 

Duchenne muscular dystrophy (DMD) is a genetic disorder that primarily affects boys and leads to severe muscle weakness due to the absence of a protein called dystrophin. Besides muscle issues, DMD can also cause neurodevelopmental, emotional, and behavioural problems. Studies on mice with DMD have shown increased startle responses to threats, which normalized when dystrophin was restored in the brain. This suggests a potential link between dystrophin and startle responses, which could be important for developing therapies. 

The paper entitled ‘Development of a Novel Startle Response Task in Duchenne Muscular Dystrophy Background’ aims to develop and test a new fear conditioning task to measure startle responses in boys with DMD and to explore the therapeutic implications. 

The task involved showing two types of visual cues: a “safe” cue and a “threat” cue paired with a loud, unpleasant noise. The researchers measured the startle responses through skin conductance response (SCR) and heart rate changes. 

The task successfully produced stronger startle responses to the “threat” cue compared to the “safe” cue as indicated by SCR and decreased heart rate when participants experienced a sudden, unpleasant stimulus. Skin conductance response (SCR) was the most reliable measure, showing consistent results across tests. 

The study optimized data processing methods to accurately measure the startle responses. 

SCR amplitude (how much the skin conductance increased) was found to be the most effective measure, with the least variance and highest reliability. 

This study confirms that the new fear-conditioning task is effective in measuring startle responses in boys with DMD. This tool could potentially lead to better therapeutic strategies to address the neuropsychiatric aspects of DMD and the research highlights the importance of considering both physical and psychological aspects of genetic disorders like DMD. The study established the best ways to measure and process these responses, setting the stage for larger studies to further explore how DMD affects emotional and physiological reactions. This could eventually lead to better understanding and management of anxiety and other emotional issues in children with DMD.