Dysmetric Dyslexia Screening Procedure

Abstract

A reading or symbol-recognition test capable of being administered to a large examination group of children which produces blurred vision only in those of the group who are possibly dysmetric dyslexic. The test which induces an eye oscillation of a selected extent which is normally below the level which produces blurred vision in those not affected with dysmetric dyslexia requires no more effort on the part of the participants than that required in watching a movie, and thus serves as an effective diagnostic screening procedure, even for pre-school children with cerebellar-vestibular dysfunctions who have not as yet even exhibited poor or refractory response to reading instruction.

Description

The present invention generally relates to methods for identifying the condition of dysmetric dyslexia attributable to a cerebellar-vestibular dysfunction, and more particularly to screening methods or procedures which can be easily and readily administered to large examination groups for the foregoing identification purpose without any time-consuming effort and without causing any discomfort to the members of the examination group.

Underlying the screening procedures according to the present invention is the discovery that the condition of dysmetric dyslexia is attributable to a cerebellar-vestibular dysfunction. This is contrary to the more widely accepted belief in the medical profession that the condition of organically determined dysmetric dyslexia is due solely or at least primarily to a dysfunction of the cortex. It suffices, however, for the present purposes to indicate that the aforesaid cerebellar-vestibular dysfunction manifested in dysmetric dyslexic children is proved by positive Rombergs, difficulty in tandem walking, articulatory speech disorders, dysdiadochokinesis, hypotonia, and various dysmetric or past pointing disturbances during finger-to-nose, heel-to-toe, writing, drawing, as well as during ocular fixation and scanning testing.

Another significant medical discovery underlying the present invention is that there exists in dysmetric dyslexic children a sub-clinical nystagmus or eye vibration at an almost imperceptable frequency or number of beats per second. Here also, for present purposes, it suffices to indicate that the existence of this sub-clinical nystagmus or eye vibration is demonstrated by electronystagmographic recordings when the eyes were closed to eliminate fixation, as this tends to inhibit nystagmus.

Although heretofore the discoveries mentioned were not known, the tests already referred to are well known and are established ways of identifying the condition of dysmetric dislexia in children arising from a cerebellar-vestibular dysfunction. Moreover, while these tests or procedures are effective, they are time-consuming to administer and, in some instances, cause great discomfort to the patient, thus making them extremely difficult to administer, particularly to pre-school children. For example, electronystagmography examinations are effectively conducted only after cold and warm caloric stimulation of the ear canal and tympanic membrane, the procedure consisting of the introduction of cold and warm water into the external ear region of the patient, thereby producing a vestibular stimulation which manifests itself in eye movements which are the subject of the electrony-stagmography recordings. During a typical examination the instrument records both eye position and eye movement velocities and thus is capable of indicating dysfunction of the cerebellar-vestibular circuits in dysmetric dyslexic children. But, as indicated, the recording is time-consuming, and the patient being examined usually experiences great discomfort during caloric stimulation and thus cannot be counted on for voluntary cooperation. It is undoubtedly because of these shortcomings that school children, even those that exhibit poor or refractory response to reading instruction, are not routinely examined to determine if they have a cerebellar-vestibular dysfunction and are dysmetric dyslexic children. Nor are pre-school children, who are not yet old enough to be given reading instruction, routinely examined to determine if they are or are prone to develop dysmetric dyslexia.

Broadly, it is an object of the present invention to provide an easy-to-administer, effective screening or diagnostic method or procedure, appropriate for large examination groups, to identify the members in such group who are possibly dysmetric dyslexic, and which procedure, in other respects as well, overcomes the foregoing and other shortcomings of the prior art. Specifically, it is an object to provide a group diagnostic screening procedure for specific identification of dysmetric dyslexia which is based on the previously mentioned medical discoveries in that it utilizes said medical discoveries by embodying the same in its formulation and in a method in which it can be practiced so that it is advantageously administered to large examination groups in an optimum minimum amount of time and without causing any discomfort to the members of the examination group. The screening procedure hereof has been found, in fact, to be more accurate than known methods in eliticing the presence of a sub-clinical nystagmus and ocular fixation and sequential scanning difficulties.

A group diagnostic screening procedure for identifying dysmetric dyslexia demonstrating objects and advantages of the present invention includes, as a significant step, the requiring of the members of the examination group to engage in a reading-type activity, i.e., visual fixation, tracking and sequential scanning, which causes a corresponding eye vibration or back-and-forth reading-type eye movement. This eye movement or eye vibration occurs at a frequency or number of beats per second which is controlled, being more specifically a function of the speed of movement of the material being visualized or read by the examination group. Such induced eye vibration is below the normal threshold level producing blurred vision but which, in additive relation to a sub-clinical eye vibration, which was previously noted as being discovered to exist in dysmetric dyslexic children, then results in a total eye vibration at a frequency or number of beats per second which is above the threshold level. Accordingly, those in the examination group experiencing blurred and/or scrambled vision are automatically identified as possibly being dysmetric dyslexic.

The above brief description, as well as further objects, features and advantages of the present invention, will be more fully appreciated by reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment of an apparatus for practicing the methods of the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a plan view of an exemplary apparatus for practicing the diagnostic screening procedures or methods according to the present invention;

FIG. 2 is a partial side elevational view, in section taken on line 2--2 of FIG. 1, illustrating further structural features of said apparatus.

FIG. 3 is a side elevational view of the apparatus showing still further structural features;

FIGS. 4a and 4b are related illustrations respectively showing the background and foreground of the visual display utilized in practicing the procedures and methods hereof; and

FIG. 5 diagramatically illustrates how said foreground and background are superimposed and used in the practice of the diagnostic screening procedures and methods hereof.

The inventive methods and procedures of the present invention are, in essence, practical ways of implementing and using a basic discovery which has been made of children afflicted with a cerebellar-vestibular dysfunction and resulting dysmetric dyslexia. This discovery is that such children have a nystagmus, which more specifically is a low order, involuntary, swinging or oscillating eye movement occurring on the average of one beat per second, herein referred to as sub-clinical. Thus, with such children, at all times there is movement in their eyes occurring at said one beat per second, which interferes with the vision of these children. This abnormal eye movement is, as noted, sub-clinical in nature, in that measurement thereof requires an electro-nystagmographic frequency recording under favorable conditions.

The foregoing sub-clinical dysfunction or nystagmus has, in turn, been traced to the presence of a cerebellar-vestibular dysfunction which prevents ocular fixation and sequential scanning of letters and words in a proper manner. Specifically, during sequential scanning or normal reading by dysmetric dyslexic children, letters and words are disordered, and letter and word scrambling or blurring results. For example, the biggest or first letter of the word is often fixated first during the slow right-to-left phase of the nystagmus. The rapid left-to-right phase often skips over several letters or a whole word until another letter is automatically fixated and scrambling or blurring results. The patient, therefore, confuses letters and words which differ only or mainly in spacial placement, i.e. b = d = p = q, a = e, .epsilon. = 3, c = u, m = w, saw = was, no-on, et cetera.

While there are already known methods of detecting dysfunctioning of the cerebellar-vestibular circuits, such methods are time consuming, one such typical method being caloric stimulation of the vestibular apparatus and utilizing electrostagmographic recordings. These prior methods often result in great discomfort to the patient requiring, for example, cold and warm caloric stimulation of the patient's ear and vestibular apparatus. In sharp contrast to the foregoing, there is described herein a rather simple procedure for early detection and prediction of dysmetric dyslexia, even at age levels difficult for detection, as in pre-school and kindergarten children. In essence, one of the methods or procedures hereof includes forcing an examination group to visually track or "read" textual material or symbols during movement. This forced reading in turn induces vibration of the patient's eyes at a frequency which, in the case of normal vision, is below the threshold level of blurred or scrambled vision. However, this induced vibration, when added to the subclinical eye vibration and nystagmus of dysmetric dyslexic children produces blurred vision in what they see, while normal children can still see clearly the moving texual material or symbols. Thus, those children in the examination group who indicate that they are experiencing blurred vision automatically identify themselves as possibly being dysmetric dyslexic.

A variation of the foregoing, which constitutes a second group diagnostic screening procedure or method according to the present invention, also uses the basic discovery heretofore mentioned of sub-clinical nystagmus in dysmetric dyslexic children, but in a slightly different way. Specifically, the examination group is required to have visual fixation on a designated point which is in the foreground of a visual display, and which display has a movable background. Thereafter, movement is imparted to the background to induce a mild nystagmus interfering with the visual fixation of those of the examination group. This interference is normally below the threshold level of normal children who can block out this interference and continue their visual fixation on the designated point. However, children aflicted with a cerebellar-vestibular dysfunction and dysmetric dyslexia, and thus having the aforementioned sub-clinical nystagmus, have difficulty maintaining their visual fixation on the designated point. In fact, the sub-clinical nystagmus results in these children losing their fixation on said designated point and instead fixating on a background point which, however, as already indicated, is moving. It has been found that children afflicted with dysmetric dyslexia have difficulty controling their vision to the extent that they can return to the task of maintaining visual fixation on the stationary designated point on the foreground, particularly with the interference caused by the moving background. In this way also, therefore, the discovered sub-clinical nystagmus is utilized as a basis for a simple, effective diagnostic screening procedure for identifying dysmetric dyslexic children in a large examination group containing same and also children with normally functioning cerebellar-vestibular circuits.

Reference is now made to the drawings wherein there is shown an appropriate projector apparatus, generally designated 10, for practicing the screening procedures or methods of the present invention. Apparatus 10, more particularly, is the one recommended for inducing a nystagmus or eye vibration of a selected extent which results in identification of dysmetric dyslexic children when in additive relation to the discovered sub-clinical nystagmus or eye vibration being experienced by said children. To the above end, and as is perhaps best illustrated diagramatically in FIG. 5, apparatus 10 includes a light source 12 which is beamed, as along the path 14, through physically superimposed transparencies 16 and 18, functioning respectively as background 19 and foreground 17, so as to produce a composite visual display 20.

The beamed projection along the path 22 is achieved with a conventional projector or optical element 24 which may be a prism or the like. The projected visual display 20 thus consists, in part, of foreground which, in turn, may consist of symbols or the illustrated words "the kitten said to," designated 17, which foreground is on the transparency 18 and is projected by the overhead projector 24 to a viewing position as part of the composite visual display 20. The other part of the display 20 consists of background symbols or the like, as exemplified by the drawing of the bear, designated 19, which is set forth on the transparency 16 and similarly is projected by the overhead projector 24 into viewing position as part of the visual display 20.

The portion of the transparency 16 containing the reproductions thereon which contribute to the projected background image 19 is set forth in FIG. 4a, while the coextensive portion of the transparency 18 containing the foreground text material 17 is set forth in FIG. 4b. As illustrated in FIG. 5, each transparency 16 and 18 is in the specific form of an elongated strip and, as will be described in greater detail subsequently, each is operatively arranged to be independently urged through movement at selected rates of speed. That is, the projected foreground 17 and background 19 can be moved at any selected speed, in feet per second, simultaneously, or the foreground material 17 can be held stationary while the background material 19 moved relative thereto, or vice versa.

As best illustrated in FIGS. 1-3, apparatus 10 includes a housing 26 for the light source 12 and has a transparent panel 28 as its upper surface. The background transparency strip 16 is arranged to be urged through movement across panel 28, being entrained on feed roller 30 at one end and on take-up roller 32 at its opposite end. To power take-up roller 32 in rotation, there is provided a spindle extension 34 on this roller, appropriately mounted in bearings, as at 36, and terminating in a driven friction disc 38. As illustrated in FIG. 1, in driving relation with disc 38 is driving disc 40 mounted on rod 42 which is shiftable in position by turning manipulation of the control knob 44 of pinion 46 in meshing engagement with rack 48. The counterpart of driving disc 40 is disc 50 mounted at the opposite end of rod 42 and shiftable into driving relation with the friction surface of driven disc 52 on the spindle extension 54 of the supply roller 30. To power the rod or drive shaft 42 in rotation, there is a step pulley 56 having a pulley drive connection to an electric motor or the like. It should be readily appreciated that not only do the driving discs 40 and 50 selectively drive the rollers 32 and 30 in rotation, but by properly locating the disc 40 relative to the rotation axis of the roller 32, control can be exercised over the speed at which roller 32 rotates, and thus the speed at which the transparency strip 16 is advanced along the path 58 beneath the overhead projector 24.

In the above regard, projector 24 is arranged in proper projecting relation to the transparency 16 and also to the transparency strip 18, by being mounted on the end of an L-shaped cylindrical rod 60. Proper positioning of the projecting element 24 is achieved by pivotally mounting rod 60, as at 62, on the housing 26.

In a very similar fashion as that already described, transparency strip 18 is also operatively arranged for movement at selected speeds in projecting relation to the overhead projecting element 24. Specifically, and as illustrated, a supply length of the transparency strip 18 is supported on the supply roller 64 and is advanced therefrom, beneath the projecting element 24, and attached to the take-up roller 66. A laterally shiftable rod or drive shaft 68 is provided having a step pulley construction 70 in driving relation via pulley belt 116 and pulley 114 with an electric motor 112 (FIG. 3). Said shaft 68 has mounted at opposite ends drive discs 72 and 74. These discs are selectively moved into driving relation with driven discs 76 and 78 on extensions 80 and 82 of the take-up roller 66 and supply roller 64, respectively. Since it is convenient to have the control for the rollers 64 and 66 on the same side as control 44, the control knob 84 thereof is located adjacent the knob 44 and has extended therefrom a rod 86 in meshing engagement, as at 88, with a further control rod 90. Rotation of rod 90 in turn causes, as best illustrated in FIG. 3, rotation in pinion 92 which is in meshing engagement with rack 94. Thus the direction of the shifting or control movement in the drive shaft 68 selects which of the driven discs 76 or 78 is to be powered in rotation. As illustrated in FIG. 1, the driving connection is made between discs 74 and 78 which produces directional movement 96 in the transparency strip 18 returning the same to the supply roller 64.

To provide additional flexibility either in the manner or in the orientation in which the component parts of the visual display are set forth in the projection being viewed by the examination group, the overhead projection 24 and the structure mounting and controlling the transparency strips 16 and 18 are rotatably mounted relative to the light source housing 26. In this respect, as illustrated in FIG. 2, mounted about the periphery of the housing 26 is a ring 98 having a lower laterally extending track 100. An outer ring-like body is mounted for rotative movement about the housing 26. Body 102 has rods connecting it to all of the previously described structures for supporting and controlling the transparency strips 16 and 18, said connecting rods being individually and collectively designated 104. The other end of body 102 has a construction providing an upper track 106. Between the tracks 100 and 106 are circumferentially spaced ball bearings 108 which enable rotational traverses in the body 102 relative to the stationary housing 26. A threadible member 110 is provided to maintain any selected rotated position of ring 102 relative to the central housing 26.

The foregoing apparatus 10 is merely exemplary of a device for producing a visual display 20 that is useful in inducing or requiring reading activity in an examination group situated in viewing position before the display 20. Specifically, this reading activity consists of the members of the examination group being required to read or recognize the display materials 17, 19 while these materials are being moved at a selected rate of speed from left to right, as viewed in FIG. 5. Experimentation with the apparatus 10 has indicated that imposing this requirement on the examination group results in each member of the group experiencing an eye vibration, or back-and-forth eye movement, at a frequency or number of beats per second which is related to the feet-per-second speed of the moving visual display 20. This eye movement at said number of beats per second, when added to the sub-clinical oscillation or beats per second characteristic of dysmetric dyslexic children inflicted with a dysfunction of the cerebellar-vestibular circuit, results in blurred or scrambled vision. In this connection, it is generally understood that in order to see something clearly, the eyes must fix on the object. When there is eye movement, however, or movement interfering with this visual fixation, the result is blurred or scrambled vision.

Children with normal functioning cerebellar-vestibular circuits can tolerate a certain extent of eye vibration or beats per second without complaining of blurred vision. This is what is referred to herein as the normal threshold level, i.e., the level of eye movements or beats per second at which there is clear vision, but beyond which there is blurred vision, for said referred to normal children. However, for dysmetric dyslexic children, the tolerance for eye vibrations or beats per second is much less, since such children start off with the previously referred to discovered sub-clinical eye vibration or nystagmus.

Using the apparatus 10 described herein, experiments with children of various ages have produced significant data on the blurring or scrambling speeds of normal children compared to dysmetric dyslexic children. The experiments utilized words set forth on the transparency strip 18 that had 11/2 inch capital letters, 3/4 inch lower case letters, and spacings of 3/4 inch between letters and four inches between words, projected as said textual material 17 approximately 6 feet into display position. The younger dysmetric dyslexic children experienced blurred or scrambled visualization of the material 17 at half the running speed in the display 20 that could be tolerated by normal children of the same age. Due to compensation, a dysmetric dyslexic child soon performs as well as a normal child, experiments indicating that this typically occurs at an average age of 10 years. Highlights of the experiment are set forth in the below table.

______________________________________ Speeds at which blurring or scrambling occurs Moving foreground 17 Fixed foreground 17 Fixed background 19 Moving background 19 feet/sec ______________________________________ Normal children 6 to 9 No blurring of of ages 4 to 8 foreground 17 years Dysmetric dyslexic 2.2 to 5 Blurring of foreground children of ages 17 at background 5 to 81/2 years speeds of 4 feet/sec ______________________________________

The specific values set forth above are not important and can vary, but what is important is that there is a significant difference, quantatively, in the speed at which the displayed matter 17, 19, produces blurred vision in so-called normal children, on the one hand, and in dysmetric dyslexic children on the other hand. This difference is effectively used, as explained herein, to identify dysmetric dyslexic children from normal children in a large examination group consisting of these children.

Another effective screening method according to the present invention which is practiced using the apparatus 10 consists of the following. The examination group is required to have visual fixation on a selected portion of the foreground material 17, such as the word "kitten." When the members of the group indicate that this has been done, for example, by appropriate hand signals, the background material 19 is then placed in motion. The moving background material 19 interferes with the ability to maintain visual fixation on the foreground image 17 for dysmetric dyslexic children only. However, since the dysmetric dyslexic children have the aforesaid sub-clinical nystagmus, this has the unfortunate result of moving their eye focus from the target 17 to an adjacent area, which consists of the moving background or symbols 19. Experimentation has indicated that dysmetric dyslexic children have difficulty getting back onto the target material 17, while normal children have no such difficulty. Thus, those members of the examination group which indicate, again by appropriate hand signals or orally, that they cannot clearly see the designated foreground target material 17 or stay focused thereon, automatically identify themselves as possibly being dysmetric dyslexic.

From the foregoing, it should be readily appreciated that the medical discoveries disclosed herein, consisting in major part of first tracing the poor or refractory response to reading instruction characteristic of dysmetric dyslexic children to a manifested dysfunction of the cerebellar-vestibular circuit, and second, a discovered sub-clinical nystagmus or eye vibration at an almost imperceptable frequency or beats per second which exist in dysmetric dyslexic children, have been carried to a further level of utility in accordance with the present invention. Specifically, these discoveries have been utilized in a noteworthy manner in the formulation, as disclosed herein, of simple, effective group diagnostic screening procedures or methods for identifying children who are possibly dysmetric dyslexic. Once identified, it is of course contemplated that these children will be further tested to confirm the existence of this condition, as for example by caloric stimulation of the vestibular apparatus. The significant point, however, is that the confirming test, which is known to be time-consuming and difficult to administer, is reserved just for this function, and an easy-to-administer screening test as described herein, and which constitutes the present invention, is effectively and advantageously used to reduce the number of members of the examination group who are to receive the confirming examination. Moreover, of presently known tests, the tests herein described have a higher degree of accuracy in identifying the existence of dysmetric dyslexia and thus even function as an improved confirming examination.

A latitude of modification, change and substitution is intended in the foregoing disclosure, and in some instances some features of the screening methods herein described can be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

Claims

What is claimed is:

1. A group diagnostic screening procedure for identifying those in said group possibly having the condition of dysmetric dyslexia, which is based on the discoveries of a cerebellar-vestibular dysfunction and resulting sub-clinical eye oscillation indicative of said condition, said procedure comprising the steps of inducing an eye oscillation of a selected extent which is normally below the threshold level producing blurred vision, but which, when in additive relation to said sub-clinical eye oscillation, is above said threshold level, and automatically identifying those experiencing blurred vision as possibly being dysmetric dyslexic.

2. The dysmetric dyslexia diagnostic screening procedure as defined in claim 1 wherein said eye oscillation which is induced in said examination group is that resulting from a visual display moving across the line of vision of said group at a selected rate of speed.

3. The dysmetric dyslexia diagnostic screening procedure as defined in claim 2 wherein for children in an age group under nine years, said rate of speed is 5 feet per second or below.

4. A group diagnostic screening procedure for identifying those in said group possibly having the condition of dysmetric dyslexia which is based on the discoveries of a cerebellar-vestibular dysfunction and resulting sub-clinical nystagmus indicative of said condition, said procedure comprising the steps of requiring the visual fixations of said examination group upon a point on the foreground of a visual display having a movable background, and then moving said background to induce a mild nystagmus interfering with said visual fixation which is normally below the threshold level producing blurred vision but which, when in additive relation to said sub-clinical nystagmus, is above said threshold level, and automatically identifying, those experiencing blurred vision as possibly being dysmetric dyslexic.

5. The dysmetric dyslexia diagnostic screening procedure as defined in claim 4 wherein said foreground material consists of words and said background material consists of pictorial representations, and said background material is moved at a rate of speed of approximately 4 feet per second or below.

6. A diagnostic screening procedure for identifying the condition of dysmetric dyslexia, which is based on the discoveries of a cerebellar-vestibular dysfunction and a resulting sub-clinical eye oscillation indicative of said dysfunction, said procedure comprising the steps of inducing an eye oscillation in a patient being examined of a selected extent which is normally below the threshold level producing blurred vision, but which, when in additive relation to said sub-clinical eye oscillation, is above said threshold level, and noting that the experiencing by said patient of blurred vision indicates the possible existence of dysmetric dyslexia.

7. The dysmetric dyslexia diagnostic screening procedure as defined in claim 6 wherein said eye oscillation which is induced in said patient is that resulting from a visual display moving across his line of vision at a selected rate of speed said display consisting of foreground and background material operatively arranged for movement independently of each other.

8. The dysmetric dyslexia diagnostic screening procedure as defined in claim 7 wherein for a patient under nine years of age said rate of speed is five feet per second or below.