Purpose of review: Progress in neurosciences, increasing computational power, and ongoing miniaturization of micro-technological components enable both a better understanding of human brain functions and development of new diagnostic and therapeutic tools. Research and development as well as clinical application of devices designed for recording neural signals from the brain or stimulating brain areas respectively raise conceptual and ethical questions.
Recent findings: Ethical issues of stimulating devices are mainly discussed in the field of deep brain stimulation. The debate with respect to its use for Parkinson's disease focuses on patients' benefit and unintended consequences - sometimes framed as questions of identity and change of personality. As deep brain stimulation is currently tested for a broad variety of different diseases, including psychiatric disorders, minimal conscious state and Alzheimer's disease, recently increasing ethical attention is paid to issues of clinical research and clinical innovation. However, with respect to recording devices, specific implications for patients' autonomy and responsibility are at the core of the discussion.
Summary: Brain-hardware interfaces need continuing ethical discussion to realize their full beneficial potential and avoid the pitfalls of hasty application.