Garnett Emily, Smith Toni, Rann Bailey, Mularoni Nicholas, Chang Soo-Eun, McAuley J Devin
University of Michigan-Ann Arbor.
Michigan State University.
Res Sq. 2025 Jun 11:rs.3.rs-6686913. doi: 10.21203/rs.3.rs-6686913/v1.
Stuttering is a neurodevelopmental condition characterized by involuntary disruptions in the rhythmic flow of speech. Notably, stuttering is associated with aberrant structure and function of the basal ganglia thalamocortical network. Separately, the BGTC network has been implicated in non-speech beat and rhythm perception. Supporting a link between the two sets of findings, children who stutter exhibit poorer auditory rhythm discrimination compared to non-stutterers, especially for complex rhythms without a consistently marked beat. For adults who stutter (AWS), data showing a link between stuttering and poorer auditory rhythm discrimination has been mixed. One possible reason may be that AWS have developed strategies for rhythm discrimination that leverage an alternative non-BGTC network dependent timing mechanism. One candidate from the timing literature is the use of an interval-based mechanism that involves the cerebellum. From this perspective, rhythm discrimination judgments for AWS would involve interval-by-interval duration comparisons, which should be expected to place a greater burden on working memory compared to the more automatic beat-based timing processes implemented by the BGTC network. To investigate this hypothesis, we combined data from three studies where AWS and age-matched controls performed the same rhythm discrimination and working memory tasks. Across studies, AWS, as hypothesized, showed a significantly stronger positive correlation between working memory and rhythm discrimination than controls where there were no (or very weak) correlations. Moreover, separate group comparison of rhythm discrimination performance for AWS with high and low working memory scores reveals no difference between controls and AWS with high working memory scores, but much poorer performance by AWS with low working memory scores compared to controls. These results support the view that AWS may mask difficulties in rhythm perception and an underlying impairment in beat-based timing by leveraging a distinct working memory dependent interval timing mechanism to discriminate rhythms.
口吃是一种神经发育状况，其特征是言语节奏的不由自主中断。值得注意的是，口吃与基底神经节丘脑皮质网络的结构和功能异常有关。另外，基底神经节丘脑皮质网络也与非言语节拍和节奏感知有关。支持这两组研究结果之间存在联系的是，与非口吃者相比，口吃儿童的听觉节奏辨别能力较差，尤其是对于没有持续明显节拍的复杂节奏。对于成年口吃者（AWS）来说，关于口吃与较差的听觉节奏辨别之间存在联系的数据并不一致。一个可能的原因可能是成年口吃者已经开发出了用于节奏辨别的策略，这些策略利用了一种依赖于非基底神经节丘脑皮质网络的替代计时机制。计时文献中的一个候选机制是使用基于间隔的机制，该机制涉及小脑。从这个角度来看，成年口吃者的节奏辨别判断将涉及逐个间隔的持续时间比较，与基底神经节丘脑皮质网络执行的基于节拍的更自动计时过程相比，这应该会给工作记忆带来更大的负担。为了研究这一假设，我们结合了三项研究的数据，在这些研究中，成年口吃者和年龄匹配的对照组执行相同的节奏辨别和工作记忆任务。在各项研究中，正如所假设的那样，成年口吃者在工作记忆和节奏辨别之间显示出比对照组更强的正相关，而对照组之间没有（或非常弱）相关性。此外，对工作记忆得分高和低的成年口吃者的节奏辨别表现进行单独的组间比较发现，工作记忆得分高的成年口吃者与对照组之间没有差异，但工作记忆得分低的成年口吃者与对照组相比表现要差得多。这些结果支持了这样一种观点，即成年口吃者可能通过利用一种独特的依赖于工作记忆的间隔计时机制来辨别节奏，从而掩盖了节奏感知方面的困难以及基于节拍计时的潜在损伤。
