Stairway Test

Mouse

Rungs

28 rungs total

2.5 cm diameter; spaced evenly every 1.5 cm.

Base of the triangle is 60 cm wide

Length on both sides: 70cm

Rat

Rungs

42 rungs total

4 cm diameter; spaced evenly every 2 cm.

Base of the triangle is 90 cm wide

Length on both sides: 100cm

Introduction

The Stairway test, introduced by Boltze et al. in 2006, was designed to assess sensorimotor deficits in rats following a stroke. This innovative apparatus requires only brief training sessions of 10-15 minutes and yields highly reproducible results. It evaluates both motor and sensory functions by having the subject climb a vertically oriented triangular ladder. The ladder’s design ensures that the home cage at the top is not visible to the subject, requiring them to learn its location through initial trials without visual cues. Similar behavioral assessments to the Stairway test include the Tilt Ladder, Horizontal Ladder, Balance Beam, and Rotarod. While many of these tasks use the fear of falling as motivation, the Stairway test’s primary motivator is the placement of the home cage at the top of the ladder. Since the ladder is nearly vertical and the home cage is out of sight, the subject must learn its position through trial and error. Unlike the Rotarod, which is a dynamic apparatus, the Stairway test is static.

Apparatus and Equipment

The Stairway apparatus features a vertically mounted triangular ladder, with the apex of the triangle serving as the base. The ladder stands 100 cm tall, with the widest rung measuring 90 cm in width. Each rung has a diameter of 0.4 cm and is spaced 2 cm apart, totaling 42 rungs. The apparatus is typically set at an inclination of 80 to 90 degrees relative to the ground, ensuring that during the experiment, the subject can only see the sides and the ceiling of the setup.

Training Protocol

The Stairway apparatus is thoroughly cleaned both before and after each experiment to ensure optimal conditions. It is well-illuminated to facilitate clear observation. Automated tracking and recording systems, such as ConductVision, Noldus Ethovision XT, can be utilized for accurate data collection and scoring. During the experiment, the subject is positioned at the apex of the ladder's first 20 cm. The home cage at the top of the ladder serves as the primary motivation for the subject to ascend. The starting point provides a clear path to the home cage, but subjects with impairments often stray from this direct route. Each daily session comprises five trials, each lasting approximately 10 seconds. Subjects are maintained under consistent temperature conditions with unrestricted access to food and water. To evaluate the effects of human umbilical cord blood cell (HUCBC) transplantation on motor performance, an artificial stroke is induced in subjects via middle cerebral artery occlusion (MCAO). Subjects are randomly assigned to receive either HUCBC cell therapy or a phosphate-buffered saline (PBS) injection 24 hours post-stroke. Baseline measurements are taken one day before the procedure. Subjects are tested daily for the first 7 days and then every other day for a total of 29 days (Boltze et al., 2006).

Sample Data

The Stairway test assesses how far the subject deviates from the central axis of the ladder. Deviations can range up to 45 cm on either side of this central point, which is designated as zero. Deviations to the left are recorded as a maximum of -45 cm, while deviations to the right are recorded as +45 cm. The data from each daily session is the average of five trials. The following sample graph depicts the deviation of the HUCBT treated subjects from the central point on the Stairway test.

Strengths & Limitations

The Stairway test has proven to be highly effective when compared to the Rotarod and the modified neurological severity score (mNSS) evaluated using a balance beam. While the Rotarod is commonly used for assessing motor deficits, it is often costly and time-intensive, typically requiring around 14 days of conditioning. In contrast, the Stairway test offers a more affordable and efficient alternative, necessitating only a brief training period of approximately 10-15 minutes. Unlike other motor deficit assessments, the Stairway test evaluates both motor and sensory functions. It provides a detailed reflection of therapeutic effects, offering a comprehensive view of motor deficits. Unlike the Horizontal Ladder test, which lacks a gravity component, the Stairway test incorporates gravitational effects, enhancing the understanding of overall motor impairments. Additionally, it can assess unilateral impairments in rodents, as evidenced by deviations from the direct route to the home cage. The primary motivation in the Stairway test is the home cage, which drives the subject’s behavior throughout the assessment. Repeated trials on the Stairway will cause muscle fatigue in the subjects. The subject’s performance may also be dependent on its weight. Thus, it is important to have a large cohort of similar weights to obtain reliable results. It is important to allow rest periods between each trial. Factors such as the age and sex can also affect the performance. Subject’s own emotional and mental status can also influence the results. Improper placement of the subject on the rungs can also lead to erroneous results. The Stairway test has proven to be highly effective when compared to the Rotarod and the modified neurological severity score (mNSS) evaluated using a balance beam. While the Rotarod is commonly used for assessing motor deficits, it is often costly and time-intensive, typically requiring around 14 days of conditioning. In contrast, the Stairway test offers a more affordable and efficient alternative, necessitating only a brief training period of approximately 10-15 minutes. Unlike other motor deficit assessments, the Stairway test evaluates both motor and sensory functions. It provides a detailed reflection of therapeutic effects, offering a comprehensive view of motor deficits. Unlike the Horizontal Ladder test, which lacks a gravity component, the Stairway test incorporates gravitational effects, enhancing the understanding of overall motor impairments. Additionally, it can assess unilateral impairments in rodents, as evidenced by deviations from the direct route to the home cage. The primary motivation in the Stairway test is the home cage, which drives the subject's behavior throughout the assessment. Repeated trials on the Stairway will cause muscle fatigue in the subjects. The subject’s performance may also be dependent on its weight. Thus, it is important to have a large cohort of similar weights to obtain reliable results. It is important to allow rest periods between each trial. Factors such as the age and sex can also affect the performance. Subject’s own emotional and mental status can also influence the results. Improper placement of the subject on the rungs can also lead to erroneous results.

Summary and Key Points

• Stairway test was first introduced by Boltze et al. (2006) to evaluate sensomotoric stroke deficits in rats.
• The novel apparatus has short training phases and is cost-effective in comparison to other tests.
• The vertically mounted triangular ladder prevents the home cage from being visible to the subject while climbing, thus, requiring the subject to learn the position of the cage over the initial trials

References

Boltze J, Kowalski I, Förschler A, Schmidt U, Wagner D, Lobsien D, Emmrich J, Egger D, Kamprad M, Blunk J, Emmrich F (2006). The stairway: a novel behavioral test detecting sensomotoric stroke deficits in rats. Artif Organs. 30(10):756-63.