Neuroprosthetic speech devices are an emerging technology that can offer the possibility of communication to those who are unable to speak. Patients with 'locked in syndrome,' aphasia, or other such pathologies can use covert speech-vividly imagining saying something without actual vocalization-to trigger neural controlled systems capable of synthesizing the speech they would have spoken, but for their impairment. We provide an analysis of the mechanisms and outputs involved in speech mediated by neuroprosthetic devices. This analysis provides a framework for accounting for the ethical significance of accuracy, control, and pragmatic dimensions of prosthesis-mediated speech. We first examine what it means for the output of the device to be accurate, drawing a distinction between technical accuracy on the one hand and semantic accuracy on the other. These are conceptual notions of accuracy. Both technical and semantic accuracy of the device will be necessary (but not yet sufficient) for the user to have sufficient control over the device. Sufficient control is an ethical consideration: we place high value on being able to express ourselves when we want and how we want. Sufficient control of a neural speech prosthesis requires that a speaker can reliably use their speech apparatus as they want to, and can expect their speech to authentically represent them. We draw a distinction between two relevant features which bear on the question of whether the user has sufficient control: voluntariness of the speech and the authenticity of the speech. These can come apart: the user might involuntarily produce an authentic output (perhaps revealing private thoughts) or might voluntarily produce an inauthentic output (e.g., when the output is not semantically accurate). Finally, we consider the role of the interlocutor in interpreting the content and purpose of the communication. These three ethical dimensions raise philosophical questions about the nature of speech, the level of control required for communicative accuracy, and the nature of 'accuracy' with respect to both natural and prosthesis-mediated speech.@en

Technologies controlled directly by the brain are being developed, evolving based on insights gained from neuroscience, and rehabilitative medicine. Besides neuro-controlled prosthetics aimed at restoring function lost somehow, technologies controlled via brain-computer interfaces (BCIs) may also extend a user’s horizon of action, freed from the need for bodily movement. Whilst BCI-mediated action ought to be, on the whole, treated as conventional action, law and policy ought to be amended to accommodate BCI action by broadening the definition of action as “willed bodily movement”. Moreover, there are some dimensions of BCI mediated action that are significantly different to conventional cases. These relate to control. Specifically, to limits in both controllability of BCIs via neural states, and in foreseeability of outcomes from such actions. In some specific type of case, BCI-mediated action may be due to different ethical evaluation from conventional action.@en

Implantable brain-computer interfaces (BCIs) are being developed to restore speech capacity for those who are unable to speak. Patients with locked-in syndrome or amyotrophic lateral sclerosis could be able to use covert speech – vividly imagining saying something without actual vocalisation – to trigger neural controlled systems capable of synthesising speech. User control has been identified as particularly pressing for this type of BCI. The incorporation of machine learning and statistical language models into the decoding process introduces a contribution to (or ‘shaping of’) the output that is beyond the user’s control. Whilst this type of ‘shared control’ of BCI action is not unique to speech BCIs, the automated shaping of what a user ‘says’ has a particularly acute ethical dimension, which may differ from parallel concerns surrounding automation in movement BCIs. This paper provides an analysis of the control afforded to the user of a speech BCI of the sort under development, as well as the relationships between accuracy, control, and the user’s ownership of the speech produced. Through comparing speech BCIs with BCIs for movement, we argue that, whilst goal selection is the more significant locus of control for the user of a movement BCI, control over process will be more significant for the user of the speech BCI. The design of the speech BCI may therefore have to trade off some possible efficiency gains afforded by automation in order to preserve sufficient guidance control necessary for users to express themselves in ways they prefer. We consider the implications for the speech BCI user’s responsibility for produced outputs and their ownership of token outputs. We argue that these are distinct assessments. Ownership of synthetic speech concerns whether the content of the output sufficiently represents the user, rather than their morally relevant, causal role in producing that output.@en

Neuroprosthetic speech technologies are in development for patients suffering profound paralysis, such as can result from amyotrophic lateral sclerosis. These patients would be unable to speak without intervention, but with neurotechnology can be offered the chance to communicate. The nature of the technology introduces a neuroprosthesis that mediates neural activity to generate synthesised speech. How word prediction coheres with speaker intentions requires scrutiny. Some future forms of prostheses, using statistical language models to predict word patterns, could be thought of as participating with communicative intent - not merely channelling it. Concepts relating to vicarious liability, may serve to clarify these issues. This column shows how technology might interact with speaker intent in cases of delegated action, and how it should be seen as participating in the implementation of user "instructions". @en