Assisted care using artificial intelligence technology is an emerging paradigm in healthcare, offering significant opportunities for improving patients' quality of life and healthcare efficiency. However, with the implementation of artificial intelligence technology in healthcare, many concerns about ethical issues regarding data usage are also developing. In this context, the article addresses the importance of ethical principles in AI-assisted care, highlighting some key aspects that need to be considered to ensure the responsible and beneficial use of this technology in healthcare. The research focuses on ethical principles regarding the implementation and development of artificial intelligence in eHealth applications, as well as the ethical implications of data use under the General Data Protection Regulation (GDPR). Use cases for applications employing users` personal data in different contexts are presented, highlighting the role of AI in eHealth, for the early detection and diagnosis of neurodegenerative conditions such as Alzheimer's and Parkinson's diseases, for personalised therapies, the continuous patient monitoring as well as for virtual healthcare specific to these diseases. A security solution based on a multimodal biometric system that can be used in eHealth applications for neurodegenerative diseases is also proposed.