Post-stroke visual midline shift syndrome

Visual midline gauge validity and repeatability: Comparison to a current clinical method

SIGNIFICANCE

Visual midline shifts are thought to occur post-stroke and be a risk factor for falls. This study investigates a new method for quantifying visual midline shifts, a first step toward developing greater understanding of visual midline shift.

PURPOSE

This study standardized the parameters of a novel visual midline gauge, compared the results with the current clinical method, and presents normative data and repeatability of both methods.

METHODS

Ninety-three participants without neurological or ocular problems were recruited in Canada and Hong Kong. In experiment 1, horizontal and vertical visual midlines were measured using the gauge for two speeds and two repositioning methods. In experiment 2, visual midline was measured for three distances using a target speed and repositioning method chosen based on the first experiment. Visual midlines were also measured using the current clinical method during both visits.

RESULTS

There were no significant effects of age, speed, study location, or repositioning method on visual midline positions (all p>0.05). For the horizontal direction, measurements at 25 cm were different from those at 50 (p=0.03) and 100 cm (p=0.001). For the vertical direction, there was no such effect. The measurements were found to be repeatable to within approximately 3°. In both visits, there were significant correlations between measurements using the visual midline gauge and the clinical method for the vertical direction (all p<.001) but not for the horizontal direction (all p>0.05).

CONCLUSIONS

The measurement of visual midline is tolerant of differences in target speed, testing method, and age of the participants, and the visual midline gauge measurements are repeatable.

Montreal Brain Injury Vision Screening Test for General Practitioners

Visual disturbances are amongst the most commonly reported symptoms after a traumatic brain injury (TBI) despite vision testing being uncommon at initial clinical evaluation. TBI patients consistently present a wide range of visual complaints, including photophobia, double vision, blurred vision, and loss of vision which can detrimentally affect reading abilities, postural balance, and mobility. In most cases, especially in rural areas, visual disturbances of TBI would have to be diagnosed and assessed by primary care physicians, who lack the specialized training of optometry. Given that TBI patients have a restricted set of visual concerns, an opportunity exists to develop a screening protocol for specialized evaluation by optometrists—one that a primary care physician could comfortably carry out and do so in a short time. Here, we designed a quick screening protocol that assesses the presence of core visual symptoms present post-TBI. The MOBIVIS (Montreal Brain Injury Vision Screening) protocol takes on average 5 min to perform and is composed of only “high-yield” tests that could be performed in the context of a primary care practice and questions most likely to reveal symptoms needing further vision care management. The composition of our proposed protocol and questionnaire are explained and discussed in light of existing protocols. Its potential impact and ability to shape a better collaboration and an integrative approach in the management of mild TBI (mTBI) patients is also discussed.

Postural Difference between the Interventions Reflecting the Concept of Mirror Therapy in Healthy Subjects

(1) Background: Mirror therapy is one of the promising interventions for the upper limb rehabilitation of stroke patients. Postural asymmetry during mirror therapy was pointed out as a possibility to influence stroke patients’ rehabilitation negatively. However, it is still difficult to find studies on the postural changes in mirror therapy concept interventions. This study compared three methods of postural differences as follows: traditional mirror therapy (mirror); displaying the real-time movement of the unaffected side on the screen above the affected side (screen); and playing a pre-recorded movement of the unaffected side on a tablet placed on a movable box where the affected hand is put inside (movable). (2) Methods: to observe a kinematic difference, we recruited 16 healthy volunteers to go through three different interventions (mirror, screen, movable). The motion capture system made observations on the postures before and during interventions, then compared and analyzed. (3) Results: while using the mirror, the sitting posture was observed to become asymmetric, and the following unique posture was observed where the target hand went further from the trunk while performing tasks. In addition, the shoulder of the target side came forward, and the difference between both elbow flexion angles was also observed. On the other hand, the screen or movable device did not cause a significant change in the sitting posture, and no additional postural differences were observed either. (4) Conclusions: mirror therapy showed a tendency to cause lateral flexion opposite the target hand, thus, creating additional postural change. However, developed methods controlled spine tilt, and enabled the keeping of the midline while sitting during the intervention.