ABSTRACT
Introduction: It is suggested that eye movement recordings could be used as an objective evaluation method of motor imagery (MI) engagement. Our investigation aimed to evaluate MI engagement in patients after stroke (PaS) compared with physical execution (PE) of a clinically relevant unilateral upper limb movement task of the patients' affected body side. Methods: In total, 21 PaS fulfilled the MI ability evaluation [Kinaesthetic and Visual Imagery Questionnaire (KVIQ-10), body rotation task (BRT), and mental chronometry task (MC)]. During the experiment, PaS moved a cup to distinct fields while wearing smart eyeglasses (SE) with electrooculography electrodes integrated into the nose pads and electrodes for conventional electrooculography (EOG). To verify MI engagement, heart rate (HR) and oxygen saturation (SpO2) were recorded, simultaneously with electroencephalography (EEG). Eye movements were recorded during MI, PE, and rest in two measurement sessions to compare the SE performance between conditions and SE's psychometric properties. Results: MI and PE correlation of SE signals varied between r = 0.12 and r = 0.76. Validity (cross-correlation with EOG signals) was calculated for MI (r = 0.53) and PE (r = 0.57). The SE showed moderate test-retest reliability (intraclass correlation coefficient) with r = 0.51 (95% CI 0.26-0.80) for MI and with r = 0.53 (95% CI 0.29 - 0.76) for PE. Event-related desynchronization and event-related synchronization changes of EEG showed a large variability. HR and SpO2 recordings showed similar values during MI and PE. The linear mixed model to examine HR and SpO2 between conditions (MI, PE, rest) revealed a significant difference in HR between rest and MI, and between rest and PE but not for SpO2. A Pearson correlation between MI ability assessments (KVIQ, BRT, MC) and physiological parameters showed no association between MI ability and HR and SpO2. Conclusion: The objective assessment of MI engagement in PaS remains challenging in clinical settings. However, HR was confirmed as a reliable parameter to assess MI engagement in PaS. Eye movements measured with the SE during MI did not resemble those during PE, which is presumably due to the demanding task. A re-evaluation with task adaptation is suggested.
ABSTRACT
We report two cases of eruptive tumors of the follicular infundibulum (TFI) with an unusual clinical presentation which has not been described previously in literature. In both cases, the appearance was strikingly similar, consisting of multiple asymptomatic hypopigmented macules on the buttocks of two Black African males, aged 38 and 55 years old. In both cases, the eruption had evolved over several months. The individual lesions were of similar size, approximately 1 cm, with irregular and ill-defined borders. Histopathological examination revealed a superficial and horizontal plate-like proliferation of keratinocytes emanating from the epidermis with multiple slender attachments. Pale keratinocytes were present within the epithelial plates. A Fontana stain showed a loss of melanin pigment from the epithelial plates. Orcein (elastic) stain highlighted an increase of the number of the elastic fibers surrounding the tumor. On the basis of these findings, a diagnosis of eruptive TFI was established for both cases. Among the various presentations of TFI, only the eruptive variant appears to be clinically distinctive, with asymptomatic hypopigmented macules usually located on the face, neck and upper trunk. Eruptive TFI should also be added to the clinical differential diagnosis of multiple hypopigmented macules on the buttocks of Black patients.