Cognitive load of walking in people who are blind: Subjective and objective measures for assessment

BackgroundAlthough walking without vision seems to carry a high cognitive cost, few studies have measured the cognitive load involved in this activity in blind people. The aim of this study was to assess the cognitive load of walking in blind people, using gait analysis, a dual task paradigm and a subjective assessment of cognitive load.MethodsIn a quantitative quasi-experimental design, 25 blind adults walked 40 meters. In one trial, participants walked normally (control condition). In another, they walked while performing an auditory simple reaction time task, and in the third trial they walked, performed the simple reaction time task and avoided obstacles. In addition to the simple reaction time task performance, walking speed was recorded, and participants provided a subjective assessment of cognitive load after each trial. Performance of participants aged less than 60 years were compared with those aged over than 60 years.ResultsWalking significantly reduced performance of the simple reaction time task; carrying out the simple reaction time task while walking significantly reduced walking performance and increased the subjective assessment of cognitive load; and simple reaction time task performance decreased and subjective assessment increased when obstacles were present. Few significant age effects were found.SignificanceWalking without vision involves a cognitive load that increases when the environment becomes complex. Each of the three methods used is relevant when assessing the cognitive load involved in walking in blind people, and could be useful in rehabilitation intervention. The results obtained allowed recommendations to be suggested for the design of technological mobility devices.     

不同气压变化速率对豚鼠耳气压伤的影响

为了解不同气压变化速率对中、内耳的影响，利用低压舱对40只豚鼠施以10种不同升、降速率（上升率／下降车为：20／20、20／100、50／20、50／100、100／20、100／100、150／20、150／100、200／20、200／100，m／s）的损伤实验。实验结果表明：前庭躯体反应的出现是因中耳腔的正压，而不是负压影响。咽鼓管机能不良和上升速率过快是本病的主要原因。下降速率增快可使鼓膜破裂数量增加，鼓膜的穿孔对避免内耳进一步损伤有积极作用，并且可因此减少发病率。圆窗膜和卵圆窗的损伤在本病中是较少发生的。变压性眩晕是一种伴随前庭终器明确病理改变的气压伤，并非一过性前庭功能失衡。     

模拟快速上浮脱险对潜艇艇员咽鼓管通气功能的影响

目的 测试模拟快速上浮脱险中潜艇艇员咽鼓管开放功能的变化,为潜艇艇员快速上浮脱险提供合理的医学保障和依据.方法 应用ET-100咽鼓管开放功能测试仪测试5名潜艇艇员在3、10 m水加压前后,10、30 m(分别以t/30、t/20速率)气加压前后,50、60 m以t/20速率气加压前后,分别检测艇员吞咽时咽鼓管(eustachian tube,ET)开放功能,并作统计学处理.结果 3、10 m水加压后ET平均开放度下降8.09%、9.79%(P>0.05);以t/30、t/20速率,10 m气加压后ET平均开放度下降11.51%,6.89%(P>0.05),30 m气加压后ET平均开放度下降58.3%、92.8%(P<0.01);以t/20加压速率进行的50、60 m气加压后ET平均开放度下降14.51%、7.56%(P>0.05).结论 各深度快速加减压对潜艇艇员咽鼓管开放功能影响差别不大,不会由于加压方式、加压速率不同而导致咽鼓管开放等级产生显著变化;快速加减压的耐受性越强,ET主动开放通气度越大.     

CT and MRI of the middle ear

Summary High-resolution computed tomography (HRCT) provides excellent contrast between osseous structures, air and soft tissue in conjunction with high spatial resolution. Therefore, thin-section HRCT with bone window setting is the method of choice for the examination of the middle ear structures. The indications are acute and chronic inflammatory changes, cholesteatoma and tumor, the “postoperative middle ear”, and malformations. In most cases, HRCT enables differentiation between inflammatory changes, cholesteatoma, and tumor. The excellent depiction of subtle osseous details enables the identification of erosions of the ossicles or of the bony walls of the mastoid cells, of osseous defects of the tegmen, of the bony labyrinth, and of the tympanic course of the facial canal. In addition, HRCT enables excellent depiction of reconstructions of the ossicles or prosthesis of the ossicles. Although HRCT is the first method of choice, magnetic resonance imaging (MRI) may provide additional information and lead to a more accurate diagnosis in some cases. This is explained by the excellent soft tissue contrast provided by MRI. In addition, MRI offers the possibility of using various pulse sequences and the administration of IV contrast material. Therefore, MRI may allow the differentiation between inflammatory changes, cholesteatoma, and tumor in those cases in which accurate diagnosis cannot be made by HRCT. The differentiation between a meningocele or meningoencephalocele and other entities such as tumors or cholesteatoma can be established by MRI. Furthermore, MRI can accurately depict cases of labyrinthitis or of neuritis of the facial nerve or of intracranial disease caused by middle ear processes, while this is not always possible by HRCT. In summary, HRCT of the middle ear is the method of choice, but MRI may provide supplementary information in those cases in which accurate diagnosis cannot be established by HRCT.      

Congenital malformations of the external and middle ear

With the focus on imaging, this paper gives a summarized view of the present knowledge on fields, which are necessary to know for a profound understanding of congenital malformations of the external and middle ear. Typical and less typical combinations of malformed parts of the ear can be derived from the embryogenesis. Clinical signs and audiometric findings lead to diagnosis in congenital aural atresia. Isolated middle ear malformations can be clinically mixed up especially with otosclerosis and tympanosclerosis. Imaging is needed for exact morphological information. In malformations of the external and middle ear, CT is the imaging modality of choice. Requirements on CT-technique as well as radiological findings including classification and pre-surgical rating are described. Morphological CT-correlates of congenital malformations and their differential diagnoses are enlisted and illustrated. The impact of CT-results on therapy is explained and actual therapeutic concepts are briefly presented.     

Three-dimensional CT of the middle ear and adjacent structures

Summary Three-dimensional (3D) computed tomography of the middle ear and adjacent structures has been carried out in two cadaveric heads from axial and coronal high-resolution images. The structures shown on the images of the walls of the tympanic cavity are illustrated. The usefulness and limitations of the technique, in this region, are discussed: use of grey level volumes at the surface of the slices and the inclusion of structural landmarks is emphasized. The 3D representations show the anatomical spacial relationships of the small structures in and around the middle ear to advantage. The information may be of use in surgical orientation.     

MRI and CT of adenomatous tumours of the middle ear

We report three adenomatous middle-ear tumours, an adenoma, an adenocarcinoma and a semimalignant adenomatous tumour, with special attention to CT and MRI findings. In all cases we found small intratympanic masses in which the ossicles were embedded. All showed contrast enhancement and similar signal intensity as brain tissue on T1- and T2-weighted images. The biological nature of the tumours was not reflected by the imaging or operative findings. Received: 10 March 2000/Accepted: 17 May 2000     

Quality assessment of 3D-CTVR,MPR and section plane techniques in ossicular chain reconstruction in middle ear cholesteatoma

AimTo assess the quality of three-dimensional volume rendered computer tomography (3D-CTVR), multi-planar reformation (MPR) and CT section plane in the fine diagnosis of ossicular chain in middle ear cholesteatoma.MethodsSixty patients with middle ear cholesteatoma were selected in this retrospective study. All cases underwent pre-operative CT scan. The respective radiologic reports of the ossicles status via three protocols were then compared to surgical findings.ResultsQuality assessment of these three protocols in the fine diagnosis of fine ossicles buried inside the soft tissue showed that both CTVR and MPR are more superior to conventional section plane, especially CTVR.ConclusionThe uses of CTVR and MPR, in conjunction with conventional section plane, are better able to show where the true and fine ossicular chain in the cholesteatoma mass is. In the final analysis, we believe that the use of CTVR and MPR techniques can have profound contributive value in future clinical work.     

Virtual CT endoscopy of ossicles in the middle ear.

The purpose of this study is to evaluate how virtual computed tomography (CT) endoscopy may help in assessing ossicles in the middle ear. Our series consisted of 96 ears of 68 consecutive patients with conducting hearing loss. All examinations were performed with a high-resolution spiral CT using axial and direct coronal planes of the temporal bone. Perspective virtual endoscopy was processed using the virtual endoscopic software. Superstructure of the stapes was difficult to evaluate on the virtual endoscopy; however, virtual endoscopy of the middle ear provides further information on the pathological conditions including congenital anomaly, posttraumatic, and inflammatory processes.