Constructional, perceptual, and spatial abilities are important, interrelated brain functions. This chapter discusses these abilities primarily in the visual modality; however, the principles and concepts apply to auditory and other modalities as well. Visual constructional tasks, such as figure copying or “clock” drawing, are the most common perceptual and spatial tests because they are quite sensitive to brain disease ( Table 10.1 ). Tests of basic visual perceptual disturbances include form or shape discrimination, figure-ground discrimination, and visual organization. Tests of basic spatial disturbances include visual search and location, neglect tasks, dressing ability, environmental orientation, and the unique visuospatial localization problems of Balint syndrome. In a second section, this chapter goes on to describe testing for complex visual problems including cortical blindness, visual object recognition, familiar face recognition, color recognition, and comparable auditory and olfactory difficulties. The positive perceptual and spatial phenomena, or illusions and hallucinations, are part of Chapter 14.
Visual Perceptual and Spatial Processing
Perceptual and spatial analysis occurs along a route from sensory input to a complete representational reconstruction of the visual world. A careful mental status examination can localize perceptual and spatial disturbances along this route. Visual primitives, such as line orientation and edge detection, contrast and spatial frequencies, luminance and color contrasts, and ocular dominance emerge in V1 (Brodmann area [BA] 17), the occipital striate cortex. Most importantly for mental status assessment, at this level, two cortical visual pathways, the ventral or “what” stream and the dorsal or “where stream,” begin to emerge ( Fig. 10.1 ). The ventral stream continues to V2 (BA18), an area involved in figure-ground analysis and other functions, through V4, an area involved in simple shape and color recognition, and ultimately to the inferior temporal cortex and object recognition. Hence ventral stream abnormalities affect basic perceptual processing and result in visual object agnosias, topographagnosia, color agnosia, and prosopagnosia. From V1, the dorsal stream continues to V2 (BA18) and dorsal V3 (BA19) involved in spatial location. A part of the dorsal stream (the “ventrodorsal” pathway to V5 [middle temporal] and inferior parietal cortex) participates in the perception of motion and the guidance of some eye movements. Dorsal stream abnormalities affect some basic perceptual processing and all spatial processing and result in hemispatial neglect, dressing “apraxia,” topographic disorientation, and Balint syndrome.
Examination of Constructional Abilities
On the mental status examination, the easiest way to screen for perceptual or spatial disturbances is through paper and pencil constructional tasks. Constructional tests include simple geometric figure copies, complex figure copy, free drawing, and clock drawing. These tests are easy to administer, do not require special stimuli for the most part, and are sensitive to disorders anywhere along the ventral and dorsal streams. Right hemisphere disorders tend to result in fragmented constructions with loss of overall spatial relations and orientation, whereas left hemisphere disorders tend to result in impoverished constructions with omission of essential features or lines. Many persons have not had occasion to draw or copy figures in decades. With these subjects, it may be more accurate if they are given one practice trial, or, in some cases, have them view you as you make the figures (marked improvement in this second process may also reflect frontal lobe executive dysfunction). Finally, many clinicians describe a failure to normally copy these figures as constructional “apraxia”; however, they are best described as constructional disturbances because they are not primary disturbances of motor programming.
Simple Figure Copy. Most examiners ask the patient to copy a simple two-dimensional figure such as a circle or a diamond, a complex two-dimensional figure such as a rectangle, or three-dimensional figures such as a box, cube, or napkin holder (“Benson figure”) ( Fig. 10.2 ). For the best constructional task performance, the examiner must be prepared beforehand. Rather than quickly drawing a stimulus on a lined progress note paper, it is best to have a preprinted design for copy, blank and unlined white sheets of paper, and a black pen or a pencil without eraser. The introductory instructions include: “Please make a copy of the picture exactly as you see it.” Those who make errors and wish to start over again should be allowed to do so but keeping both copies.
There are different methods for grading the drawings. The examiner looks for abnormal or fragmented spatial relationships, absence of detail or impoverished essential features, stimulus-boundedness (“closing-in” or drawing over the master copy), loss of three-dimensional perspective, or neglect of one part of the drawing. For simpler constructions, there are suggested grading systems for the copy of a circle (closed to within 1/8” = 1; circular = 1); of a diamond (4 sides = 1; 4 closed angles = 1; sides of equal length = 1); and of a rectangle (both figures 4-sided = 1; overlaps resembles original = 1). For the cube and Benson figure, a suggested grading system is included in Fig. 10.2 .
Complex Figure Copy. The Rey-Osterrieth Complex Figure is the best known complex figure test ( Fig. 10.3 ), but there are alternative ones, such as the Taylor figure and others. These constructional tasks have the advantage of having a formal scoring system and normative data for assessing the patient’s performance. The examiner gives the patient a blank piece of paper and places the stimulus figure in front of him or her. The complex figure task requires the patient to copy the entire figure as best as he or she can, and, although not given a time limit, the patient receives encouragement to complete it. To assess strategy, the examiner may change the patient’s pencil or pen to different colored ones at different points in the drawing, thus indicating the sequence and strategy for copying the figure. The scoring system includes 18 specific items (Chapter 17, Fig. 17.1). As an additional visual memory task, they may reproduce the complex figure from memory ( Chapter 9 ), and the strategy for completion can be further analyzed as an executive task (Chapter 13).
Freehand Drawing Tasks. These tasks add the element of visual imagery and remove the guide of a predetermined drawing to copy. The examiner provides the patient with a blank sheet of paper and instructs the patient to draw a house, a dog, a flower (e.g., a “daisy in a flowerpot”), or even a person (the “draw-a-person” test). The patient instructions are: “I would like you to draw simple pictures. I know that you may not be an artist, but please draw the pictures as well as you can.” Evaluate the drawings in terms of the features noted for simple figural constructions. In addition to perceptual and spatial disturbances, these drawings can also reflect semantic deficits (see Chapter 9 ).
Clock Drawing. The freehand drawing of a clock is a sensitive measure of perceptual and spatial difficulty, but it is also affected by attention, language comprehension, numerical knowledge, and executive functions. It can be administered in a number of ways, but the best may be the presentation of a blank piece of paper with the instructions to simply “draw a clock.” After the patient draws the clock circle with the numbers, the examiner then has the patient put in the hands to read “10 after 11” or, alternatively, “5 past 4.” There are many scoring systems for the clock, some of which attempt to distinguish the different cognitive functions that impact on clock drawing ( Table 10.2 ). The easiest is to evaluate for the contour of the circle, the order and quadrant placement of the numbers (which can be within or outside of the circle), and the presence of two hands, a short hour hand and a long minute hand, meeting near the center of the clock face ( Fig. 10.4 ).
| Constructional Testing |
| • Simple figure copies, e.g., simple geometric, cube, Benson figure |
| • Complex constructions, e.g., Rey-Osterrieth |
| • Free drawings, e.g., “draw-a-person” |
| • Clock drawing |
| • Block assembly, picture arrangement, freehand constructions, paper folding |
| Basic Perceptual Testing |
| • Shape discrimination |
| • Obscured figures, e.g., cross-hatched |
| • Figure-ground, e.g., hidden/embedded figures or overlapping (Poppelreuter) figures |
| • Visual integration, e.g., incomplete or cut-up drawings |
| • Global-local processing, e.g., Navon figures |
| • Top-down gestalt, e.g., proximity, similarity, continuity, connectedness, closure |
| Basic Spatial Testing |
| • Visual search and localization, e.g., dot circling, complex drawing/picture scanning |
| • Hemispatial neglect, e.g., line bisection, visual search, gap test, double stimulation |
| • Sensory, motor, and conceptual neglect tasks |
| • Dressing “apraxia” |
| • Topographic orientation, e.g., new route, familiar route, draw route, reading map |
| • Balint syndrome (simultanagnosia, optic ataxia, oculomotor apraxia) |
| • Line orientation, e.g., Benton judgement of line orientation |
| • Contrast sensitivity and spatial frequencies |
| • Mental spatial rotation |
| • Movement detection (kinetopsia) |
| • Depth perception (stereopsis and monocular cues) |
| Testing for Cortical Blindness and Visual Agnosias |
| • Cortical blindness, e.g., Anton-Babinski syndrome, blindsight, Riddoch phenomena |
| • Visual object agnosias, e.g., object/picture comprehension tasks, visual appearance and matching, drawing/copying tasks, atypical/unusual views perception tasks |
| • Prosopagnosias, e.g., face recognition, face-face matching, name-to-face matching, name-identity matching |
| • Topographagnosia, e.g., landmark recognition |
| • Color agnosia, e.g., name, indicate, and sort colors |
| __ 1. There is an attempt to indicate a time in any way. |
| __ 2. All marks or items can be classified as either part of a closure figure, a hand, or a symbol for clock numbers. |
| __ 3. There is a totally closed figure without gaps (closure figure). |
| Score Only if Symbols for Clock Numbers are Present: |
| __ 4. A “2” is present and is pointed out in some way for the time. |
| __ 5. Most symbols are distributed as a circle without major gaps. |
| __ 6. Three or more clock quadrants have one or more appropriate numbers: 12–3, 3–6, 6–9, 9–12 per respective clockwise quadrant. |
| __ 7. Most symbols are ordered in a clockwise or rightward direction. |
| __ 8. All symbols are totally within a closure figure. |
| __ 9. An “11” is present and is pointed out in some way for the time. |
| __10. All numbers 1–12 are indicated. |
| __11. There are no repeated or duplicated number symbols. |
| __12. There are no substitutions for Arabic or Roman numerals. |
| __13. The numbers do not go beyond the number 12. |
| __14. All symbols lie about equally adjacent to a closure figure edge. |
| __15. Seven or more of the same symbol type are ordered sequentially. |
| Score Only if One or More Hands are Present: |
| __16. All hands radiate from the direction of a closure figure center. |
| __17. One hand is visibly longer than another hand. |
| __18. There are exactly two distinct and separable hands. |
| __19. All hands are totally within a closure figure. |
| __20. There is an attempt to indicate a time with one or more hands. |
| ___ TOTAL SCORE (maximum score of 20) |
The examiner, where indicated, may want to test constructional ability with additional tests, such as block assembly and picture arrangement. Most of these tests, however, require special stimuli or procedures for testing and scoring performance and are highly dependent on visuomotor coordination and basic motor ability. For example, block construction can employ four Koh’s blocks, which have sides that are red, white, or half red and half white. The examiner presents pictures of different four-block arrangements and asks the patient to take the blocks and make a design that looks like the pictures. Cut-up pictures can also be arranged, much like a jigsaw puzzle. The examiner can use other constructional tools, including tinker toys and readily available items such as match sticks or toothpicks, for freehand constructions. One additionally potentially useful constructional task that does not require blocks or constructional tools is paper-folding. The examiner folds the paper in different ways, for example, exactly in half, quarters, two triangles, along the diagonal, et cetera, and asks the patient to fold their paper in an identical way.
Examination of Basic Perceptual Abilities
Basic Visual Form Discrimination. If more in-depth testing is needed, the examiner evaluates basic perception. When viewing images, people must be able to recognize form at the basic, geometric level. The reconstruction and eventual recognition of basic forms and shapes is a process that underlies the ability to recognize objects, which are made up of basic forms and shapes. The easiest screen is to have the patient match two or three previous constructions with the correct choice out of a field of different geometric forms ( Fig. 10.5 ). The examiner should note whether, in matching the figures, the patient uses a slow, feature-by-feature analysis rather than a rapid global analysis of configuration. This evaluation can also include a multiple-choice matching task using complex forms or shapes or objects in unconventional views. Each figure is presented with four other match figures varying in shape, rotation, or distortion of the figure, and the patient is asked to indicate which match figure corresponds to the stimulus figure. An alternative screening procedure, which is also easy to do in a clinical encounter, is to ask the patient to identify figures obscured by cross-hatching ( Fig. 10.6A ). This screen overlaps with figure-ground tests.
Figure-Ground D iscrimination. When viewing images, people experience some figures projecting into the foreground, whereas others recede into the background. The brain organizes the visual field into figures that stand out from their surroundings (ground). Often “figure” and “ground” alternate or compete with each other. This figure-ground processing, which is evident at the V2 level, is a basic perceptual process that can be tested with hidden or embedded figures ( Fig. 10.6B ). The patients may also identify three or four overlapping figures made up of overlapping line drawings, originally popularized as the Poppelreuter figures test.
Visual Integration and Global-Local Processing. When viewing images, people automatically organize what they see into figures, objects, and scenes. This process of integration allows for the apprehension of intact figures from dilapidated or incomplete ones. The inability to apprehend and integrate at the single form or object level is sometimes called “integrative agnosia,” which is related to the inability to apprehend and integrate multiple objects at a scene level. The examiner tests visual organization with incomplete or cut-up drawings ( Fig. 10.6C ). The Street Figures are part of the original Street Completion Test and consist of incomplete pictures that have been used to examine perceptual integration. Alternatively, the examiner can present cut-up pictures such as compose the Hooper Visual Organization Test. The cut-up figures are fragmented objects that have to be reconstructed mentally. Global-local processing is easily tested with the “Navon” figures, which consist of letters or numbers made up of smaller letters or numbers ( Fig. 10.6D ). Patients may recognize the smaller numbers or letters and miss the global one. Finally, it is important to present a complex drawing to the patient (also part of visual search testing), generally representing a familiar scene ( Fig. 10.7 ), and assess whether the patient can identify the whole theme or situation, as well as the constituent parts.
