VT Works

Spatial Correspondence

In Part Five, the square was tilted, requiring the patient to preserve the identity of the shape while reorganizing the complete pattern around a diagonal reference. This represented a significant conceptual and developmental change. The patient could no longer depend exclusively upon the familiar horizontal and vertical framework established during the earlier levels.

Part Six introduces a different type of demand. The patient must continue to reproduce the relationships within the pattern, but the location of the complete design must now correspond to its location on the model. It is no longer sufficient to reproduce the general configuration somewhere on the work surface. Each block must be positioned within the same area of space.

More Than the General Configuration

Throughout the earlier levels, the patient could reproduce the pattern without being required to place it in the exact location occupied by the model. The blocks needed to demonstrate the correct relationships, but the entire construction could be shifted to another part of the work surface. A pattern placed several inches to the right of the model could still be considered accurate if its internal organization was preserved.

Spatial correspondence changes that expectation. The patient must reproduce both the configuration of the pattern and its location within the surrounding field. The triangle must remain correctly oriented to the square, the parallelogram must maintain its relationship to the other blocks, and the complete arrangement must occupy the corresponding position on the patient’s work surface.

The patient must therefore answer two different spatial questions:

• “How are the blocks arranged in relation to one another?”
• “Where is the complete pattern located within the available space?”

A patient may understand the first relationship without consistently recognizing the second. The construction may be internally accurate but positioned too high, too low, too far to one side, or too close to the edge of the work surface.

The Plexiglass Becomes Part of the Pattern

To introduce spatial correspondence, the Vision Therapist and patient each use a matching sheet of clear plexiglass. The Vision Therapist constructs a parquetry pattern on one sheet, and the patient reproduces it on the other. The edges of the plexiglass establish a shared spatial boundary, allowing the patient to compare the location of the blocks within two equivalent visual fields.

The plexiglass is not simply a surface upon which the pattern is constructed. Its edges become part of the spatial information that must be considered. A block may be close to the upper edge, several inches from the lower edge, or positioned within one quadrant of the sheet. The patient must recognize these relationships and reproduce them along with the pattern itself.

Without a clearly defined boundary, the patient may have difficulty determining whether the complete construction has been shifted. The plexiglass creates a consistent frame of reference against which position can be judged.

Relative Position and Position Within the Field

Spatial correspondence requires the patient to coordinate two levels of organization. The first is the position of each block relative to the other blocks. The second is the position of the complete design relative to the edges of the plexiglass.

A patient might accurately reproduce a triangle touching the upper-left edge of the square and a parallelogram extending from its lower-right corner. However, the patient may place the entire arrangement in the center of the plexiglass when the model is located near the upper-right corner. The relationships within the pattern are correct, but the relationship between the pattern and the surrounding field has not been reproduced.

The Vision Therapist should distinguish between these two types of error. Moving one block may correct an internal relationship, but correcting the position of the entire pattern requires the patient to recognize that all the pieces have been displaced together.

Useful questions include:

• “Are the blocks arranged correctly?”
• “Is the complete pattern in the same place?”
• “Which edge of the plexiglass is closest to the pattern?”
• “Is your pattern higher or lower than mine?”
• “Is the space around your pattern the same as the space around mine?”
• “Would moving one block correct the difference, or would the entire pattern need to move?”
• “What could you use to judge where the pattern belongs?”

These questions help the patient separate the organization within the pattern from the position of the pattern within the larger field.

Establishing a Starting Location

The location of the first block can influence the placement of every block that follows. If the patient begins too far to the left, the relationships among the pieces may remain accurate while the entire construction becomes displaced. By the time the pattern is completed, correcting its location may require moving every block.

Before placing the first piece, the patient should be encouraged to consider where the complete pattern will fit on the plexiglass. This requires planning beyond the immediate placement of a single block. The patient must anticipate how much space the remaining pieces will occupy and how the construction will relate to the boundaries of the work surface.

The Vision Therapist might ask:

• “Where will you begin?”
• “How did you decide that the first block belongs there?”
• “How much space will the rest of the pattern require?”
• “Which edge can help you judge the starting position?”
• “If you begin there, where will the final block be located?”
• “Do you have enough room for the complete pattern?”

The goal is not to provide the patient with the correct starting location. The goal is to help the patient develop a method for establishing that location independently.

Looking Between Two Spatial Fields

The patient must repeatedly shift attention between the model and the developing construction. Each look provides information about shape, orientation, distance, direction, and position within the surrounding space. The patient must retain enough of that information to make a purposeful placement after returning attention to the work surface.

This process places demands upon visual memory, visual attention, and central-peripheral integration. The patient may focus centrally upon one block while using peripheral information to appreciate the location of the complete pattern. The patient must then move from consideration of the individual part to consideration of the whole, recognizing that the accuracy of one block does not guarantee the spatial accuracy of the complete design.

A patient may look frequently between the two patterns but continue to gather only limited information with each glance. Another patient may study the model for a longer period but lose the information before placing the next block. The number of looks is less important than the quality of the information obtained and the patient’s ability to use it.

The Vision Therapist can make several important observations:

• Does the patient look only at individual blocks, or does the patient also consider the complete pattern?
• Does the patient use the edges of the plexiglass as spatial references?
• Does the patient establish an appropriate starting location before constructing the pattern?
• Does the patient notice when the complete design begins to drift?
• Can the patient maintain the correct internal relationships while adjusting the overall position?
• Does the patient compare the amount of open space surrounding each construction?
• Does the patient shift efficiently between the model and the work surface?
• Can the patient remember location and orientation after looking away?
• Does the patient develop a consistent strategy for checking the complete pattern?

These observations can help determine whether the difficulty involves block-to-block relationships, position within the visual field, memory for spatial information, or coordination among all three.

The Importance of Open Space

The empty area surrounding the blocks provides important information. The patient must recognize not only where the pattern is located, but also how much space exists between the pattern and the boundaries of the plexiglass.

A construction may appear internally correct while still being displaced because the patient has attended only to the blocks. Comparing the open space above, below, and beside each pattern can make the positional difference easier to recognize.

The Vision Therapist might ask:

• “Which pattern has more space above it?”
• “Is the space to the left the same in both?”
• “Which edge is closest to the square?”
• “Where do you see the largest open area?”
• “If the blocks are correct, what else could make the patterns look different?”
• “What would happen to the open space if the complete pattern moved?”

These questions direct attention toward the negative space surrounding the pattern without immediately identifying the correction that should be made.

Superimposition Provides Exact Feedback

Superimposition becomes particularly useful during spatial correspondence because it reveals both internal and positional differences. When one sheet of plexiglass is placed over the other, correctly corresponding blocks should overlap. If the patient has reproduced the configuration accurately but shifted the complete pattern, the blocks may maintain the same relationships while failing to align with the model.

The Vision Therapist might ask:

• “Do the blocks overlap?”
• “Are the differences within the pattern, or has the complete pattern shifted?”
• “Do all the pieces appear to be displaced in the same direction?”
• “Which part of the pattern is closest to the correct location?”
• “How far would the complete construction need to move?”
• “Would you move one block or all of the blocks?”
• “What will happen to the surrounding space when the pattern is moved?”

After the patient identifies the discrepancy, the sheets should be separated before any changes are made. The patient must use the information gained through comparison to plan and complete the correction.

The process remains:

Construct. Compare. Identify. Predict. Modify. Recheck.

At this level, the patient must determine whether the correction belongs within the pattern or applies to the complete pattern as a unit.

Supporting Spatial Correspondence

The Vision Therapist can adjust the level of difficulty without removing the central demand of the activity. A simple pattern containing only a few blocks can be positioned near a clearly defined edge of the plexiglass. Once the patient consistently reproduces that location, the pattern can be moved farther from the boundaries, where fewer external references are immediately available.

The demand can also be adjusted by changing the size and complexity of the pattern, the number of blocks, the amount of open space, or the position of the model. A pattern located near a corner may provide two nearby boundaries for reference. A pattern placed near the center requires the patient to judge its position without depending upon close contact with an edge.

The Vision Therapist can use several strategies to adjust the demands of the activity:

• The Vision Therapist can begin with a small number of blocks.
• The model can be placed near an edge or corner.
• The initial patterns can contain clear internal relationships.
• The patient can identify a starting location before touching the blocks.
• The patient can compare the surrounding space before making corrections.
• The distance between the model and the patient’s work surface can be increased.
• The model can be moved farther from the edges of the plexiglass.
• The number of blocks can be increased.
• Separation, pockets, or a tilted square can be introduced.
• The number of visual comparisons permitted can be reduced.
• The patient can reproduce the pattern after a brief delay.

Each change should serve a specific purpose. The goal is not to make the activity difficult for its own sake, but to identify the conditions under which spatial organization begins to lose stability.

Role Reversal

During role reversal, the patient creates a pattern on the plexiglass, and the Vision Therapist reproduces it. The Vision Therapist may intentionally reproduce the internal configuration accurately while shifting the complete design to another location.

The patient must determine whether the error involves the relationships among the blocks or the location of the complete pattern.

The patient might explain:

• “The blocks are arranged correctly, but the whole pattern is too far to the right.”
• “Your square is in the correct position relative to the triangle, but the design is too low.”
• “You copied the pattern, but you did not copy where I placed it.”
• “All the pieces need to move together.”
• “The space around your pattern does not match mine.”

This language demonstrates that the patient understands spatial correspondence as something more than reproducing the general configuration.

The Vision Therapist can also make a smaller positional error by shifting only one block. The patient must then distinguish between an error affecting an individual relationship and one affecting the entire construction.

Determining Mastery

Mastery of spatial correspondence should be demonstrated across several unfamiliar patterns and in different areas of the plexiglass.

The patient should demonstrate the ability to:

• Reproduce the internal configuration of the pattern.
• Position the complete pattern within the corresponding area of space.
• Use the edges of the plexiglass as spatial references.
• Consider the open space surrounding the pattern as part of the visual information.
• Establish an effective starting location.
• Plan for the space required by the complete construction.
• Shift attention efficiently between the model and the work surface.
• Distinguish an individual placement error from displacement of the complete pattern.
• Predict whether one block or the complete pattern must be moved.
• Use superimposition to identify positional differences.
• Make purposeful corrections after the model is removed.
• Explain the strategy used to reproduce both the configuration and location of the pattern.

Mastery does not require perfectly measured placement. The patient should, however, demonstrate an organized and repeatable method for reproducing the pattern within the corresponding region of the visual field.

Every Block in Its Place

Spatial correspondence brings the parquetry hierarchy into a more precisely defined field. The patient must continue to identify shapes, preserve their orientations, and reproduce the relationships among them. The patient must now also recognize where the complete pattern belongs.

The plexiglass provides a common boundary, but the patient must learn how to use that boundary. The surrounding space becomes meaningful, the placement of the first block becomes part of the plan, and the position of the whole must remain available while each individual part is considered.

The patient is no longer reproducing only what the pattern looks like. The patient is reproducing where it exists.

Stay tuned for Part Seven…The Finale!