Neurological Assessment Protocol for Animal Stroke Models

A 10 criteria neurological assessment score was adapted from previous work (27 (link)) based on the common system for neurologic dysfunctions in large animals (39 ). This study specifically focused on the functional deficits observed in animals following transient MCAo, including changes in demeanour, behaviour, and motor dysfunction (Table 1). A score of 0 was considered normal, with a possible total score of 36 indicating severe deficit.
Each criterion was scored at the time of assessment upon agreement of two independent assessors. Observations of level of consciousness and state of activity gave a score for animal demeanour (Table 1, criterion 1). Animals who were comatose warranted euthanasia, and no further investigations were performed. Abnormalities in animal behaviour were assessed by cumulative scores for presence of food debris in the mouth indicating inability to properly masticate, torticollis, evidence of abnormal flexion at the fetlock and/or carpus/tarsus joints, general ataxia or dysmetria in limb movements, and circling (Table 1, criteria 2, 3, 4, 5, and 6 respectively). Circling behaviours (criterion 6) were monitored prior to animal handling on assessment days by undisturbed video recording of the animal for 10 min within their home pen environment.
Three postural reaction tests (Table 1, criteria 7, 8 and 9) were conducted by forcefully shifting the animal's weight over their centre of gravity on individual limbs and assessing their ability to correct the movement. Criterion 7 refers to “hemi-standing”, which evaluated the animal's ability to correct and co-ordinate fore- and hind-limbs during a lateral movement on the left and right side of the body. Criterion 8 refers to the “hopping reaction” which assessed forelimbs individually to determine the animal's ability to correct the limb during lateral movement. Additional quarter scores were allocated in criteria 7 and 8 if the animal exhibited inability to fully extend a limb upon release, causing ‘knuckling' on the ground. Criterion 9 encompassed “lateral dragging”, which involved the forced lateral movement of each individual limb and assessment of the animal's ability to return the limb back to the medial starting position. Quarter scores were given for criterion 9 if animals dragged a limb on return (0.25/limb) or if correction back to original position was only partial (0.25/limb). Scores for hemi-standing, hopping, and lateral drag were incorporated into a single postural reaction measure for the contralateral and ipsilateral side of the body, respectively. Forced forward movement of the animal on both forelimbs (“wheelbarrowing”, Table 1, criterion 10) assessed for any sideways deviation, indicative of hemineglect and potential hemiparesis, which was reported independently. All scoring took place approximately 2 h prior to commencing motion capture procedures.