Do GPs have the techniques for 'watchful waiting' in glue ear?

'Watchful waiting' for glue ear in children within primary care as a precursor or alternative to surgery is one of the increasing pressures on general practitioners (GPs) to limit outpatient referrals. An equipment survey questions whether primary care is properly equipped to 'watch', given the limited access to audiological equipment that might objectively underpin a decision on when 'waiting' should end.     

Two-state compression of spectral tilt: individual differences and psychoacoustical limitations to the benefit from compression

A psychoacoustic rationale was developed for a hearing aid design in which compression of spectral tilt was incorporated without any instantaneous nonlinear distortion. This involved switching between a 'flat' and a 'rising' frequency response; the switching was done slowly to avoid audible transients and was controlled by feedback derived from comparison of output levels in low- and high-frequency channels, approximating voiced/unvoiced detection. The effect of this switching process was to narrow the distribution of spectral tilt values compared with the input. Asynchrony between the switching and the triggering speech structures was avoided by also delaying the signal path. Unfortunately, hearing-impaired listeners performed more poorly on the switching system than on either of the control 'flat' or 'rising' frequency-responses. An explanation is offered (on the basis of growing evidence from perceptual experiments) of the perceptual importance of temporal envelope contours within individual frequency bands. It was possible, in part, to predict individuals' results in the switching condition from age and audiometric or psychoacoustic characteristics. The results suggest a modification to the switching design, and they point to an intrinsic limit to the ability of all hearing aids of the compression type to enhance intelligibility.     

The effect of attentional cueing on conscious awareness of stimulus and response

Attending to a cued location in space leads to faster reaction times when a stimulus is presented there. The reasons for this attentional effect, and its specific locus in the information-processing chain between stimulus and response, remain unclear. One suggestion is that attention speeds the conscious detection of stimuli. Surprisingly, this possibility appears not to have been tested directly. To resolve this question, we asked subjects to make simple responses to lateralised targets that followed either a valid, invalid or neutral cue, and to judge the perceived time of the target onset, or of their response, by delayed report of the position of a clock hand. Our results showed that only a small and non-significant part of the attentional effect is due to delayed conscious awareness of the stimulus. The greater part of the attentional effect is localised either subsequent to conscious detection of stimuli or occurs in a separate, parallel processing stream from that which generates the motor response. Electronic Publication     

Patterns of coordinated multi-joint movement

In multi-joint reaching movements, the motor system may choose any one of an infinite set of possible joint rotations to move the hand between given start and target positions. In order to find out whether reaching movements are represented in Cartesian hand coordinates or in joint coordinates, it is necessary to measure whether hand paths or joint paths have lower variability. We have measured hand paths and rotations of shoulder, elbow and wrist joints simultaneously in five subjects reaching in four orientations in the horizontal plane. As in earlier studies, we found a preference for nearly straight hand paths, despite different patterns of joint rotation for different orientations of movement. However, movements in three of four orientations showed a single principal joint, which rotated essentially without reversals. This may reflect optimisation in the motor system, preferring the simplest pattern of joint control for a desired hand path. We used generalised Procrustes analysis to quantify the variability in shape of repeated paths in hand space and joint space. Results showed that hand paths were less variable than the joint angles used to realise them, due to the kinematic redundancy of the limb, suggesting that hand paths, rather than joint angles, are directly represented by the motor system. Nevertheless, movements with straighter hand paths, on average, and those requiring coordinated activity at both shoulder and elbow joints also showed more variability in the shape of the hand path. Other orientations such as movement across the body use primarily a single joint and are less variable at the cost of a slightly curved path. These results suggest that coordinating multiple joints to produce a straight hand path has a definite computational cost. The motor system may perform a trade-off between the benefits of planning reaching movements as straight hand paths and the computational simplicity of executing them using patterns of joint rotation which simplify multi-joint coordination.     

The relative effects of external spatial and motoric factors on the bimanual coordination of discrete movements

The ability to coordinate the two hands effectively is a fundamental requirement for many everyday tasks. To investigate how bimanual coordination is achieved we asked subjects to perform discrete bimanual key-press responses under conditions in which the motoric (i.e., muscles employed) and external spatial (i.e., direction of movement in external space) relationships between the actions of the left and right index fingers were systematically varied. Subjects made simultaneous right and left index finger key-presses in response to an auditory tone. The right finger always made downward flexion movements whilst the left finger either flexed in a downward/upward direction, or extended in a downward/upward direction. Unimanual control trials of each movement type for both hands were also performed. Reaction times for each hand (RTs) and the inter-response interval (IRI) were recorded . Right hand RTs were significantly affected only when the left finger performed motorically different actions, but were unaffected by the external spatial direction in which the left hands actions were made. The IRI results followed a similar pattern with the worst coordination (highest IRI) occurring when the left finger performed different motor actions to the right finger regardless of the direction of the left hand movement. In contrast to other recent results from experiments examining oscillatory tasks (e.g., Mechsner et al. 2001), our results suggest that in discrete tasks there is a dominance of the motor relationship between the hands over the external spatial relationship.     

I think, therefore I manage

Thirty healthcare managers were asked about the moral assumptions underlying their attitudes to the job. Pat Haggard reports her findings.     

Interference between gait and cognitive tasks in a rehabilitating neurological population

OBJECTIVES: To quantify the extent of interference between gait and cognitive tasks after brain injury; to investigate whether such interference is common to various cognitive tasks, or confined to specific cognitive modules; to investigate whether such interference declines during recovery from brain injury. METHOD: Fifty participants were recruited from a neurological rehabilitation unit (33 people, 75% of sample); the stroke rehabilitation ward of an acute hospital (11 people, 20%); and a young disabled unit (six people, 5%). Measures of stride duration were taken in single task conditions, and in conjunction with each of four cognitive tasks. Outcome measures were dual task decrements in gait and in cognitive task performance. RESULTS: Overall, a 7% decrement in stride duration was recorded under dual task conditions compared with single task, with stride duration being significantly longer during simultaneous performance of each cognitive task. There was a 4% decrement on average in cognitive task performance under dual task conditions, with significant decrements being recorded for word generation while walking and paired associate monitoring while walking. A significant correlation (r=0.45) was found between dual task decrements and scores on a standard measure of disability-the Barthel activities of daily living scale-but the correlation with 10 m walking time was not significant (r=0.18). CONCLUSION: Interference between cognitive tasks and motor control activities such as gait is a problem in neurological rehabilitation settings. Interference between cognition and locomotor tasks may be important in assessing neurological patients' ability to function independently, and in designing therapies for both cognitive and motor rehabilitation.     

参麦注射液对内皮细胞增殖和迁移的影响

目的：探讨参麦注射液对血管生成的影响。方法：采用MTT法检测参麦注射液对牛血清和肿瘤细胞条件培养液促进的牛主动脉内皮细胞增殖的影响，采用琼脂糖刮除法检测参麦对牛血清和肿瘤条件培养液促进的牛内皮细胞迁移的影响。结果：在含10％新生小牛血清培养液中和在肿瘤细胞条件培养液中，参麦都能明显抑制牛主动脉内皮细胞增殖，且呈量效关系，对肿瘤细胞条件培养液诱导的内皮细胞迁移抑制作用显著。方法：参麦能抑制牛内细胞增殖和迁移，具有抑制血管生成的作用。