  The advent of miniature biosensors has generated numerous opportunities for
deploying wireless sensor networks in healthcare. However, an important barrier
is that acceptance by healthcare stakeholders is influenced by the
effectiveness of privacy safeguards for personal and intimate information which
is collected and transmitted over the air, within and beyond these networks. In
particular, these networks are progressing beyond traditional sensors, towards
also using multimedia sensors, which raise further privacy concerns.
Paradoxically, less research has addressed privacy protection, compared to
security. Nevertheless, privacy protection has gradually evolved from being
assumed an implicit by-product of security measures, and it is maturing into a
research concern in its own right. However, further technical and
socio-technical advances are needed. As a contribution towards galvanising
further research, the hallmarks of this paper include: (i) a literature survey
explicitly anchored on privacy preservation, it is underpinned by untangling
privacy goals from security goals, to avoid mixing privacy and security
concerns, as is often the case in other papers; (ii) a critical survey of
privacy preservation services for wireless sensor networks in healthcare,
including threat analysis and assessment methodologies; it also offers
classification trees for the multifaceted challenge of privacy protection in
healthcare, and for privacy threats, attacks and countermeasures; (iii) a
discussion of technical advances complemented by reflection over the
implications of regulatory frameworks; (iv) a discussion of open research
challenges, leading onto offers of directions for future research towards
unlocking the door onto privacy protection which is appropriate for healthcare
in the twenty-first century.
