Delivering effortless hearing is our core ambition with every hearing aid feature we design so people with hearing loss, regardless of cognitive capability, gain the optimal listening experience with the least amount of effort. 
How does it take to obtain "Effortless Hearing"?
How does compressor speed relate to cognitive capacity? How does the Variable Speed Compressors (VSC) used in Widex hearing aids allow for the best speech understanding? To answer these technical questions, let's begin with the simple concept of "Effortless Hearing". 

Effortless hearing is a concept at the core of Widex design to ensure the optimal listening experience with the least amount of effort. This philosophy is a guiding principle behind how Widex designs its hearing technology to produce a clear sound for all wearers. In a Hearing Review article, Dr. Francis Kuk answered these questions and more to best explain the benefits of Variable Speed Compressors.  

How does compressor relate to cognitive capacity in relationship with hearing aids?
bringing individualism to your patient's appointment, offering a hearing that differentiates signal processing strategies for individual differences. Cognitive capacity should aid during the hearing aid fitting. What is compression speed? Advantage of more gain for soft sounds and less gain for loud sounds. Benefits of VSC more audibility of soft speech of wearer with mild-to-moderate loss, better sound quality at a high input level (both soft and loud), better temporal waveform at high input levels for those with severe hearing loss and improved speech intelligibility in quiet and noisy settings. 
Are hearing aids being fit properly?
Here is one question an audiologist should ask themselves before fitting a hearing aid; do I know the cognitive capability of the patient? Knowing the answer to this question will help the hearing professional best apply the right signal processing. Whether the patient has a good or poor working memory, they need the signal to be audible before they can detect and understand sounds. This means audibility is equally important for the people who have both good or poor working memory. Additionally, the temporal structure of the sounds is important in the "naturalness" of the sound quality. Temporal information is also equally important for people with either good or poor working memory.