4.4.3 Electroencephalogram
Electroencephalogram (EEG) is a technique that measures changes in
activity within brain systems and has been used to assess pain
associated with evoked potentials (measurable electrical signals in the
nervous system that originate from a controlled stimulus) and
resting-state EEG166-168. EEG is readily available and
relatively easy to use, although its uses in studies of OUD are
limited169. EEG has been used to and evaluate OUD
symptoms (e.g., impulsivity, emotional dysregulation, and reward
sensitivity)170-172 and co-occurring chronic pain, as
well as assess who may benefit most from
analgesics173.
As sleep quality directly influences wellbeing and poor sleep worsens
the experience of pain174, the use of EEG for
assessment of pain in patients with OUD presents as a promising, largely
unexplored opportunity. For example, Lewis and
colleagues175 demonstrated, using EEG techniques, that
heroin use suppressed REM sleep as well as deep non-REM sleep; notably,
these findings were extended to methadone and morphine by Dimsdale and
collaborators176. Discovery and validation of these
abnormal sleep patterns in OUD patients through EEG provoked research
into ameliorating these issues with novel treatments, subsequently
reducing future risks of patient relapse177. EEG has
proven to be a powerful tool in preclinical, human laboratory, and
clinical research and has the potential to be a useful tool in
diagnostics and risk assessment for patients with OUD in a clinical
setting. The use of EEG in investigating how these measurements apply to
pain for patients with OUD is limited and presents an opportunity for
future biomarker research.