Anterior cingulate implants for tinnitus: report of 2 cases

Abstract

893case report J Neurosurg 124: [893][894][895][896][897][898][899][900][901] 2016 N oNpulsatile tinnitus is the perception of a sound in the absence of an external source and is therefore often considered a phantom sound. 30 It is related to abnormal activity in the auditory and nonauditory brain areas, 48 which can be altered by neuromodulation techniques. 24 As tinnitus is most commonly related to auditory deafferentation 20 with 30,31 or without 59 audiometric hearing loss, it has been regarded as maladaptive auditory memory traces 5 attempting to reduce the inherent auditory uncertainty associated with auditory deafferentation.11 Apart from abnormal activity, pathological functional connectivity is also associated with the presence of tinnitus as demonstrated by electroencephalography (EEG), 57 magnetoencephalography (MEG), 38,39 and functional MRI (fMRI). 26,27 Thus, it has been proposed that the phenomenologically unified percept of tinnitus can be considered an emergent property of multiple, parallel, dynamically changing, and partially overlapping subnetworks, each with a specific spontaneous oscillatory pattern and functional connectivity signature. 17 Functional imaging studies using source-localized EEG and MEG have shown that tinnitus distress is related to a network involving the anterior cingulate cortex (ACC), anterior insula, and parahippocampal area, 6,22,56 whereas the auditory cortex is involved in the perceived tinnitus intensity. 44 The distress subnetwork is predominantly lateralized to the right, in contrast to a similar network encoding depression that is lateralized to the left. 21 The loudness and distress networks are clearly separable even though they interact. Communication between these different subnetworks is proposed to occur at hubs, brain areas that are involved in multiple subnetworks simultaneously. These hubs can take part in each separable subnetwork at different frequencies. ComabbreviatioNs ACC = anterior cingulate cortex; BA = Brodmann area; BOLD = blood oxygen level-dependent; d = dorsal; DLPFC = dorsolateral prefrontal cortex; EEG = electroencephalography; fMRI = functional MRI; HADS = Hospital Anxiety Depression Scale; MEG = magnetoencephalography; NRS = numeric rating scale; r = repetitive; sg = subgenual; sLORETA = standardized low-resolution electromagnetic tomography; tDCS = transcranial direct current stimulation; TENS = transcutaneous electrical nerve stimulation; TMS = transcranial magnetic stimulation; TQ = tinnitus questionnaire. Tinnitus can be distressful, and tinnitus distress has been linked to increased beta oscillatory activity in the dorsal anterior cingulate cortex (dACC). The amount of distress is linked to alpha activity in the medial temporal lobe (amygdala and parahippocampal area), as well as the subgenual (sg)ACC and insula, and the functional connectivity between the parahippocampal area and the sgACC at 10 and 11.5 Hz. The authors describe 2 patients with very severely distressing intractable tinnitus who underwent transcranial magnetic st...

Deep brain stimulation of the ventral anterior limb of the internal capsule for treatment-resistant depression: possibilities, limits and future perspectives

“…Patients with tinnitus who had no functional connectivity between the implant site and a tinnitus-generating network did not benefit from implanted electrodes, whereas those who did benefitted, similarly to what has been shown for non-invasive stimulation and invasive stimulation for other brain disorders (14). These results suggest that the clinical effect of brain stimulation might critically depend on the presence of functional connectivity between the stimulation target and the disease-generating network (13), and that preoperative analysis of the functional connectivity in patients with depression could theoretically be of use to determine the target of the electrode implant. This also suggests that one target does not fit all, and that biomarkers such as preoperative functional connectivity might become more important to select the individualized target.…”

“…This has been clearly demonstrated in cortex stimulation, both at the level of the auditory cortex (12) and anterior cingulate cortex (13). Patients with tinnitus who had no functional connectivity between the implant site and a tinnitus-generating network did not benefit from implanted electrodes, whereas those who did benefitted, similarly to what has been shown for non-invasive stimulation and invasive stimulation for other brain disorders (14).…”

“…For example, intriguingly, the subgenual anterior cingulate cortex, a potential target for treating depression with DBS, shows divergent changes between the two depression subtypes, with increased connectivity in the non-melancholic and decreased connectivity in the melancholic subsets (15). This could explain why not everybody responds to DBS of the subgenual anterior cingulate cortex, as stimulation of a hypoconnected area might be non-effective (13), and that different targets might be required for the two different subtypes of depression.…”

State of the Art: Novel Applications for Cortical Stimulation

“…Two very severely distressed intractable tinnitus patients underwent rTMS with a double cone coil targeting the dACC and were subsequently implanted with a bilateral paddle electrode on their dACCs via an open midline approach. One of the patients responded to the implant and one did not, even though phenomenologically they expressed the same tinnitus characteristics, tinnitus loudness, and tinnitus distress . The responder has remained dramatically improved for longer than two years, with 6 Hz burst stimulation at the dACC.…”

Visions on the future of medical devices in spinal cord stimulation: what medical device is needed?

“…The Proclaim™ and the Protégé™, are the first real upgradable stimulator/internal pulse generators, and set the tone for the future in developing medical devices for spinal cord stimulation and beyond. It is highly likely that root ganglion stimulation will also benefit from this upgradable approach as preliminary reports demonstrate that some of the new stimulation designs are indeed also beneficial for cortex stimulation, both somatosensory cortex [66], auditory cortex [29], cingulate cortex [67] and peripheral nerve stimulation [30,31], and there is no reason to a priori believe the same rationale will not be applicable for deep brain stimulation and dorsal root ganglion stimulation. The future is upgradeable.…”