Medical literature does not have clear consensus on inter-rater reliability of PS assessment by different oncology health care professionals (HCPs) although it plays an important role in treatment decision and prognosis for oncology patients. Eastern Cooperative Oncology Group (ECOG) and Karnofsky performance status (KPS) scores are commonly used for this purpose by oncology HCPs around the world. This study was conducted to find variability or similarities in assessment of PS among the different oncology HCPs. A survey based on four hypothetical clinical scenarios was devised and sent to 50 oncology HCPs to assess the PS using ECOG PS tool. No significant variations in PS assessment by oncology HCPs was noted in our study sample.
The predominant role of the primary motor cortex (M1) in motor execution is well acknowledged. However, additional roles of M1 are getting evident in humans owing to advances in noninvasive brain stimulation (NIBS) techniques. This review collates such studies in humans and proposes that M1 also plays a key role in higher cognitive processes. The review commences with the studies that have investigated the nature of connectivity of M1 with other cortical regions in light of studies based on NIBS. The review then moves on to discuss the studies that have demonstrated the role of M1 in higher cognitive processes such as attention, motor learning, motor consolidation, movement inhibition, somatomotor response, and movement imagery. Overall, the purpose of the review is to highlight the additional role of M1 in motor cognition besides motor control, which remains unexplored.
Deterioration of motor and cognitive performance with advancing age is well documented, but its cause remains unknown. Animal studies dating back to the late 1970s reveal that age-associated neurocognitive changes are linked to age-dependent changes in synaptic plasticity, including alterations of long-term potentiation and depression (LTP and LTD). Non-invasive brain stimulation techniques enable measurement of LTP- and LTD-like mechanisms of plasticity, in vivo, in humans, and may thus provide valuable insights. We examined the effects of a 40-s train of continuous theta-burst stimulation (cTBS) to the motor cortex (600 stimuli, three pulses at 50 Hz applied at a frequency of 5 Hz) on cortico-spinal excitability as measured by the motor evoked potentials (MEPs) induced by single-pulse transcranial magnetic stimulation before and after cTBS in the contralateral first dorsal interosseus muscle. Thirty-six healthy individuals aged 19–81 years old were studied in two sites (Boston, USA and Barcelona, Spain). The findings did not differ across study sites. We found that advancing age is negatively correlated with the duration of the effect of cTBS (r = −0.367; p = 0.028) and the overall amount of corticomotor suppression induced by cTBS (r = −0.478; p = 0.003), and positively correlated with the maximal suppression of amplitude on motor evoked responses in the target muscle (r = 0.420; p = 0.011). We performed magnetic resonance imaging (MRI)-based individual morphometric analysis in a subset of subjects to demonstrate that these findings are not explained by age-related brain atrophy or differences in scalp-to-brain distance that could have affected the TBS effects. Our findings provide empirical evidence that the mechanisms of cortical plasticity area are altered with aging and their efficiency decreases across the human lifespan. This may critically contribute to motor and possibly cognitive decline.
28 November 2012 in European Journal of Neuroscience
Transcranial magnetic stimulation (TMS) is a useful tool to induce and measure plasticity in the human brain. However, the cortical effects are generally indirectly evaluated with motor‐evoked potentials (MEPs) reflective of modulation of cortico‐spinal excitability. In this study, we aim to provide direct measures of cortical plasticity by combining TMS with electroencephalography (EEG). Continuous theta‐burst stimulation (cTBS) was applied over the primary motor cortex (M1) of young healthy adults, and we measured modulation of (i) MEPs, (ii) TMS‐induced EEG evoked potentials (TEPs), (iii) TMS‐induced EEG synchronization and (iv) eyes‐closed resting EEG. Our results show the expected cTBS‐induced decrease in MEP size, which we found to be paralleled by a modulation of a combination of TEPs. Furthermore, we found that cTBS increased the power in the theta band of eyes‐closed resting EEG, whereas it decreased single‐pulse TMS‐induced power in the theta and alpha bands. In addition, cTBS decreased the power in the beta band of eyes‐closed resting EEG, whereas it increased single‐pulse TMS‐induced power in the beta band. We suggest that cTBS acts by modulating the phase alignment between already active oscillators; it synchronizes low‐frequency (theta and/or alpha) oscillators and desynchronizes high‐frequency (beta) oscillators. These results provide novel insight into the cortical effects of cTBS and could be useful for exploring cTBS‐induced plasticity outside of the motor cortex.