Dual-task effects of talking while walking on velocity and balance following a stroke.

BACKGROUND: Therapists and nurses often use verbal instruction in the rehabilitation of mobility following stroke. This study aimed to determine whether performing a verbal cognitive task while walking adversely affected patients' balance and velocity. METHODS: There were two counterbalanced conditions: walking only and walking and concurrent cognitive activity. The cognitive activity used was to give one of two verbal responses to two verbal stimuli. An electronic GaitMat measured gait velocity and balance (double support time as a percentage of stride time). RESULTS: 11 people with stroke participated in the study (five women and six men, mean age 72 years, SD 9). They were on average 120 (SD 48) days post-stroke. Velocity decreased (P=0.017) and double-support time as a percentage of stride time increased (P=0.010) when the cognitive activity was added to the test. CONCLUSIONS: Performing a verbal cognitive task while walking adversely affected stroke patients' balance and gait velocity. Susceptibility to disruption varied within the patient group, suggesting clinical heterogeneity. Further research is required before changes to clinical practice are justified.

Identification without naming: a functional neuroimaging study of an anomic patient.

The neural correlates of identification and name retrieval have proved difficult to characterise because both occur highly automatically in normal language processing. Thus, although some evidence points to the left anterior temporal cortex (ATC) as a brain region underlying these functions, its relative role in semantic and lexical retrieval processes is still a matter of debate. Positron emission tomography (PET) was used to measure regional cerebral blood flow responses to famous and non-famous visually presented faces and buildings in a severely anomic patient and in six control subjects, while they were performing a same-different matching task. Because the patient was able to identify the stimuli that he could not name, it was possible to investigate whether the left ATC would respond when identification occurred without name retrieval. Both the patient and the controls activated the left ATC when famous stimuli were compared with non-famous stimuli. This result supports the hypothesis of a predominantly semantic function of the left ATC.