UK exceptional case driving application outcomes in post-stroke homonymous hemianopia: results from a clinical study

PURPOSE

We report results in relation to returning to driving in the UK under the exceptional cases rule for visual field loss.

METHODS

The Hemianopia Adaptation Study is a prospective clinical study recruiting adult stroke survivors with new onset homonymous hemianopia. The mobility assessment course (MAC) was used to measure navigational scanning. Car drivers were offered a 1-year post-stroke assessment to consider referral for driving assessment.

RESULTS

Of 144 participants, 51 were eligible for driving assessment, with 13 (25.4%) accepting appointment for UK Driving and Vehicle Licensing Agency (DVLA) referral. A statistically significant difference in gender and baseline Barthel (stroke severity) scores was found between those requesting referral and those declining (p = 0.046; p < 0.001). MAC outcomes were significantly different, with those referred having a lower percentage of target omissions (9.0%) and faster mean course completion time (46.0 s), than those not referred (28.3%/72.5 s) (p = 0.006/p < 0.001). Twelve of the 13 referred were offered a driving assessment by the DVLA. All 12 passed and returned to driving.

CONCLUSIONS

It is possible for individuals with post-stroke homonymous hemianopia to return to driving, where exceptional cases criteria are met. There is evidence to support use of the MAC as a clinical measurement of adaptation.IMPLICATIONS FOR REHABILITATIONIndividuals with post-stroke homonymous hemianopia should be fully informed regarding driving regulations that can differ between countries and sometimes different states within a country, as well as provided with the support and opportunity to consider a return to driving if appropriate.Professionals providing care within the stroke multi-disciplinary team should be aware that it is possible for patients with homonymous hemianopia to return to driving, when exceptional cases criteria are met.The mobility assessment course (MAC) should be considered as a clinical measurement of adaptation in homonymous hemianopia.A cut-off score of ≤25% omissions on MAC could be employed to determine those likely to adapt to hemianopia long-term and potentially return to driving.

The mobility assessment course: A ready-to-use dynamic measure of visuospatial neglect

The Mobility Assessment Course (MAC) is a tool to measure visuospatial neglect in a dynamic fashion. Although the MAC has been shown to dissociate between patients with and without neglect, it remains unclear whether it is applicable in clinical settings. We evaluated the MAC regarding its (1) feasibility as a diagnostic tool as part of standard care, (2) construct validity, and (3) underlying constructs and potential confounders. A consecutive sample of stroke patients admitted to inpatient rehabilitation completed the MAC, shape cancellation, line bisection, and/or Catherine Bergego Scale (CBS) as part of the standard assessment. To assess feasibility, we computed the percentage of patients who completed the MAC. Construct validity was tested by evaluating MAC performance between patients with and without neglect and controls. Finally, a regression analysis was conducted to assess underlying constructs and potential confounders of MAC performance (i.e., level of mobility and lesion side). The MAC was completed by 82% of patients (N = 182/223; of whom 145 completed all tasks). Patients with neglect performed worse on the MAC (indicating more severe neglect) compared to patients without neglect and controls. The MAC had a lower sensitivity and higher specificity than paper-and-pencil tasks and the CBS. Performance on shape cancellation, line bisection, and CBS were predictors of MAC performance. Level of mobility and lesion side did not predict MAC scores, indicating that these factors do not confound its reliability. To conclude, the MAC is an easy-to-implement tool to evaluate neglect in a dynamic manner, which can be administered in addition to conventional paper-and-pencil tasks.

Adaptation to post-stroke homonymous hemianopia - a prospective longitudinal cohort study to identify predictive factors of the adaptation process

PURPOSE

To determine any factors that predict how an individual will adapt to post-stroke hemianopic visual field loss, with close monitoring of the adaptation process from an early stage.

MATERIALS AND METHODS

The Hemianopia Adaptation Study (HAST) is a prospective observational longitudinal cohort clinical study. Adult stroke survivors (n = 144) with new onset homonymous hemianopia were monitored using standardised mobility assessment course (MAC) as the primary outcome measure of adaptation.

RESULTS

Several baseline variables were found to be good predictors of adaptation. Three variables were associated with adaptation status at 12-weeks post-stroke: inferior % visual field, % total MAC omissions, and MAC completion time (seconds). Baseline measurements of these variables can predict the adaptation at 12 weeks with moderate to high accuracy (area under ROC curve, 0.82, 95% CI 0.74-0.90). A cut-off score of ≤25% target omissions is suggested to predict which individuals are likely to adapt by 12-weeks post-stroke following gold standard care.

CONCLUSIONS

Adaptation to hemianopia is a personal journey with several factors being important for prediction of its presence, including MAC outcomes and extent of inferior visual field loss. A clinical recommendation is made for inclusion of the MAC as part of a functional assessment for hemianopia.Implications for rehabilitationThe mobility assessment course (MAC) should be considered as an assessment of mobility/scanning in the rehabilitation of patients with homonymous hemianopia.A cut-off score of ≤25% omissions on MAC could be employed to determine those likely to adapt to hemianopia long-term.Targeted support and therapy for patients with significant visual loss in the inferior visual field area should be considered.