Deep Learning (DL)-based solutions have shown promising performance in assessing neonatal pain. However, the occlusion of the visual modality (face and body) is common in clinical settings due to several factors, including a prone sleeping position, low light, or swaddling. In such scenarios, other pain signals, such as audio signals, can be used as the major behavioral signs of pain. Although DL-based methods are proposed to assess pain from audio, these methods lack transparency and explainability (black box), which can decrease the user's trust in the automated decision. In this work, we visualize the neonate's audio signal as a spectrogram image to classify it as pain or no pain and present an instance-based approach for explaining the decision of the black-box model. Further, this work provides an analysis of the most helpful and harmful training instances using an influence score followed by assessing their impact on pain prediction. Experimental results demonstrate that the proposed approach can detect and remove harmful instances, eventually leading to a compressed dataset. Our results also show that the proposed work can add explainability to the current DL-based pain detection methods, which can enhance users' trust and provide a viable approach toward pain assessment in clinical settings.

Although concept-based approaches are widely used to explain a model’s behavior and assess the contributions of different concepts in decision-making, identifying relevant concepts can be challenging for non-experts. This paper introduces a novel method that simplifies concept selection by leveraging the capabilities of a state-of-the-art large Vision-Language Model (VLM). Our method employs a VLM to select textual concepts that describe the classes in the target dataset. We then transform these influential textual concepts into human-readable image concepts using a text-to-image model. This process allows us to explain the targeted network in a post-hoc manner. Further, we use directional derivatives and concept activation vectors to quantify the importance of the generated concepts. We evaluate our method on a neonatal pain classification task, analyzing the sensitivity of the model’s output for the generated concepts. The results demonstrate that the VLM not only generates coherent and meaningful concepts that are easily understandable by non-experts but also achieves performance comparable to that of natural image concepts without the need for additional annotation costs.

As machine learning increasingly plays a crucial role in various medical applications, the need for improved explainability of these complex, often opaque models becomes more urgent. Influence functions have emerged as a critical method for explaining these black-box models. Influence functions measure how much each training sample affects a model's predictions on test data, with previous research indicating that the most influential training samples usually exhibit a high degree of semantic similarity to the test point. Building on this concept, we propose a novel approach that modifies the influence function for more precise influence estimations. This involves adding a new weighting factor to the influence function based on the similarity of the test and training data. We employ cosine similarity, Euclidean distance, and the structural similarity index to calculate this weight. The modified influence method is evaluated on a neonatal pain assessment model to explain the decision, revealing excellent performance in identifying influential training points compared to the baseline method. These results show the effectiveness of the proposed approach in elucidating the decision-making process.

Infant cries serve as a primary indicator of distress and pain; however, distinguishing pain-related cries from those triggered by other needs remains a challenging task, even for trained professionals. Timely and accurate pain assessment is essential for appropriate medical intervention, particularly in preverbal infants who cannot express their needs verbally. Recently, Deep Learning (DL) models have demonstrated significant potential in addressing this challenge by enabling automated and efficient pain assessment through audio signal processing. In this survey, we review methods for pain assessment from infant cry sounds, covering deep learning architectures, modern Transformer-based models, and emerging Vision-Language Model (VLM) pipelines. The review includes approaches that integrate Mel-spectrogram representations of cry audio with multimodal model frameworks to improve robustness, interpretability, and cross-modal reasoning in pain detection. By summarizing recent advancements and identifying limitations and open challenges in current methodologies, this review aims to provide insights into future research directions that may enhance the robustness, generalizability, and clinical applicability of automated infant pain assessment tools.