Characterization of a clinical olfactory test with an artificial nose

Abstract

Clinical olfactory tests are used to address hyposmia/anosmia levels in patients with different types of olfactory impairments. Typically, a given test is employed clinically and then replaced by a new one after a certain period of use which can range from days to several months. There is a need to assess control quality of these tests and also for a procedure to quantify their degradation over time. In this paper we propose a protocol to employ low-cost artificial noses for the quantitative characterization of olfactory tests used in clinical studies. In particular, we discuss a preliminary study on the Connecticut Chemosensorial Clinical Research Center Test kit which shows that some odorants, as sensed by an artificial nose, seem to degrade while others are potentiated as the test ages. We also discuss the need to establish a map of correspondence between human and machine olfaction when artificial noses are used to characterize or compare human smell performance in research and clinical studies.

Simultaneous real-time monitoring of multiple cortical systems

“…Overall, these factors can make human ECoG experiments less controlled than non-invasive neuroscientific studies in healthy human subjects or invasive studies in animals. At the same time, in these respects, our present study is similar to the many other ECoG-based studies that have been described in the literature [37, 17, 23, 16, 22, 18, 39]. Despite the issues described above, the results presented in our present and other ECoG studies are usually consistent with expectations based on the general human neuroanatomy or on results from other imaging modalities.…”

“…Previous studies [47, 22, 37, 12, 23, 16, 38, 35] have demonstrated retrospectively that individual brain processes, such as movement, movement planning or auditory processing can be reliably decoded from ECoG signals. However, it was not clear to what extent these decoding models could be applied in real time or generalize over time.…”

“…Previous (mostly offline) studies have shown that it is possible to relate specific functional parameters to brain signal features for isolated brain functions. These demonstrations usually involved the motor or auditory systems, and were accomplished using non-invasive electroencephalography (EEG) [10, 11, 3], invasive electrocorticography (ECoG) [12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28], or invasive single-neuron recordings [29, 30, 31, 32, 33, 34]. However, it remains unclear whether the relationships between different functional parameters and brain signals are conserved during real-world tasks, which tend to be complex and multi-modal and often occur in varied and unpredictable contexts.…”

“…ECoG signals in humans are usually acquired from people with epilepsy who undergo invasive pre-surgical monitoring for localization of epileptic foci. Recent offline studies have shown that ECoG amplitudes in certain frequency bands carry substantial task-related information, such as motor execution and planning, auditory processing and visual-spatial attention [36, 37, 17, 23, 38, 16, 22, 18, 39, 27]. Most of this information is captured in the high gamma range (around 70–110 Hz), suggesting that high gamma activity provides reliable information about neural activity of local cortical populations.…”

On the Usage of Linear Regression Models to Reconstruct Limb Kinematics from Low Frequency EEG Signals

“…These potentials originate approximately two seconds prior to movement onset developing the Bereitschafts potential (BP) or readiness potential (RP) [35], and rebound during movement execution developing the motor potential (MP). BPs have been used to detect movement intention [36], [37] while MPs have been used to detect movement parameters such as direction [31], [38]. In these approaches the extracted motor information are general movement parameters (i.e., the intention to move, the direction of the movements) usually detected before movement onset or just after movement initiation.…”