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This paper describes the Rivermead Behavioural Memory Test (RMBT)-a short test of everyday memory problems with four parallel forms. It was administered to 118 control subjects aged between 16-69 years with a mean IQ of 106 (range 68-136). The limit of normal performance was established on this group and cut-off points were determined for individual components of the test. The test was also given to 176 brain-damaged people and its validity assessed both by correlating RMBT scores to performance on existing tests, to subjective ratings from patients and carers and to observation by therapists of memory lapses. Validity, parallel form and interrater reliability all proved to be high. It is concluded that the RBMT is a short, reliable, and valid test of everyday memory problems.

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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. (J Neurol Neurosurg Psychiatry 2000;69:479-486)

Background Walking while performing another task (eg, talking) is challenging for many stroke survivors, yet its neural basis are not fully understood. Objective To investigate prefrontal cortex activation and its relationship to gait measures while walking under single-task (ST) and dual-task (DT) conditions (ie, walking while simultaneously performing a cognitive task) in stroke survivors. Methods We acquired near-infrared spectroscopy (NIRS) data from the prefrontal cortex during treadmill walking in ST and DT conditions in chronic stroke survivors and healthy controls. We also acquired functional magnetic resonance imaging (fMRI) and NIRS during simulated walking under these conditions. Results NIRS revealed increased oxygenated hemoglobin concentration in DT-walking compared with ST-walking for both groups. For simulated walking, NIRS showed a significant effect of group and group × task, being greater on both occasions, in stroke survivors. A greater increase in brain activation observed from ST to DT walking/ simulated walking was related to a greater change in motor performance in stroke survivors. fMRI revealed increased activity during DT relative to ST conditions in stroke patients in areas including the inferior temporal gyri, superior frontal gyri and cingulate gyri bilaterally, and the right precentral gyrus. The DT-related increase in fMRI activity correlated with DT-related change in behavior in stroke participants in the bilateral inferior temporal gyrus, left cingulate gyrus, and left frontal pole. Conclusion Our results provide novel evidence that enhanced brain activity changes relate to dual task motor decrements.