Which term refers to the modifications in responses that have a significant impact on a client's expression?

The term "amplification" refers to the process of enhancing or increasing the intensity of a client's expression, particularly in a therapeutic or social work setting. When practitioners use amplification, they might encourage clients to elaborate on their feelings or experiences, which can lead to a deeper understanding of the client's emotional state or situation. This technique can help to illuminate key themes or issues that may be at the core of the client's challenges, allowing for a more focused and effective intervention.

In contrast, the other options represent different concepts. Attenuation involves diminishing or reducing the intensity of a response, which would not support a deeper exploration of a client's expression. Alteration implies making changes but lacks the specific focus on enhancing a response. Clarification involves making something clear or easier to understand but does not emphasize increasing the emotional impact or depth of the expression itself. Thus, amplification is the most relevant term for describing modifications that significantly enhance a client's expression.