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Evaluation of Cognition, Balance, and Sensory Processing Disorders (SPDs) in Patients following Exposure to Visual & Non-R...


Evaluation of Sound Sensory Processing and SPD Disorders with the Boss BR-8 Metronome Player

Originally Published 2002    Revised: November, 2006

BY: Stephen Dolle, Ph.D. (Unofficial)

STUDY SUMMARY: This study was undertaken to evaluate vestibular and sensory processing disorder (mainly sound sensitivities) complaints in individuals with hydrocephalus to a set of auditory, visual, and balance stimuli, and to determine the causal connections; and whether new auditory and balance THERAPIES might be created to de-sensitize or compensate patients with these deficits. Though we only studied persons with hydrocephalus, we postulate our findings are applicable to many other neurological disorders involving sensory processing disorders, or SPDs. Such additional disorders would likely include autism, PTSD, post TBI, ADHD, post-tumor, etc. We measured sensory processing responses to rhythmic and non-rhythmic (un-syncopated,  repetitive) audio digital recorded rhythms from a 50-patern Boss Mixer/metronome samples. We documented a causal relationship between sensitivity to non-rhythmic auditory stimuli or sound, and chronic neurological (sensory processing) deficits, defined by headache, irritability, nausea, disorientation, decrease in cognition and attention, and malaise. The deficit responses, among others, are sometimes termed sound sensitivities, sensory processing disorder (SPD), sensory overload, cognitive event, behavioral meltdown, behavioral outburst, and neuro-hypersensitivities. In a separate test, we also found a positive balance response and (vestibular) deficits in patients having chronic sensory processing (SPD) complaints, in our a gaze challenge test on the Airex balance pad. 

We have been following the increasing reports of sensory processing disorders in patients with hydrocephalus, autism, PTSD, and so on, and set out to evaluate common "white noise" or non-rhythmic sound patterns in congested urban areas (i.e. noise pollution). We felt we might develop sensory strengthening therapies to address these growing complaints. Of interest in our study, we observed some momentary relief in sensory complaints when participants were exposed to "syncopated" rhythms from the same Boss metronome. It suggested a combination audiotape or CD of the two opposing patterns might be helpful in treating sensory overload complaints on a longer term basis, and we created an audiotape for this purpose. We later learned that moderate exposure and participation in live drumming might strengthen an individual's threshold to sensory overload stimuli. These therapies could then be employed in the home, classroom, and work settings for persons with at risk sensory processing disorders to improve tolerance to offensive (un-syncopated) sound. We postulate the therapies might also enhance cognition, concentration, and productivity.

STUDY HYPOTHESIS: Vestibular deficits and increased sensitivities (sensory overload disorder) to sound and motion often follow changes in the brain following hydrocephalus, autism, ADHD, post TBI, migraine, PTSD, and others. There is a known association between chronic neurological complaints and sensory processing disorders (SPDs) and decreased tolerance to light, sound, and motion, with an associated decrease in cognitive status. We postulate the sequela is due in part to fatigue on the brain and sensory processing centers also used in compensatory adjustment. Affected individuals are thought to be more visually dependant on maintaining "vestibular" or balance orientation, and typically report more sensory processing complaints. Neuro-compensatory therapies utilize "cognitive engagement" and include such therapies are EMDR, meditation biofeedback, breath work, and forms of pain management. Some individuals can adjust to vestibular disruptions, like being in a boat at sea, without developing nausea and vomiting. Research suggests they may compensate with specifically tailored vestibular, auditory, and visual therapies. 

The primary interest of our study was in evaluating the poor responses to non-rhythmic or un-syncopated auditory rhythm patterns, which we undertook using a metronome. We postulated that when auditory hypersensitivities are present, the critical causative element seemed more in the "non-rhythmic pattern" of the sound, and less dependent on volume or tempo (speed) of the pattern. We hope to draw a correlation between specific non-rhythm patterns, and degree of adverse response. We further hoped we could establish some "parameters" to define "normal" and "abnormal" response ranges, or intolerance, to auditory stimuli. In today's Western culture and lifestyle, children of all ages and adults are continually exposed (bombarded) to a variety of auditory stimuli through the sounds of household and work site machinery, music and television, electronic games, and public gatherings, including noise in classrooms. A metronome with (50) different rhythmic auditory patterns, and volume and tempo adjustments, was employed to emulate the variety of rhythmic patterns found in everyday life.

Our study interest was also caused by new favorable results with EMDR Therapy in treating Post Traumatic Stress Disorder, or PTSD. In PTSD, chronic neurological complaints and neuro-hypersensitivities. We felt the hippocampus, located near the balance center of the brain, might be involved in chronic sensory processing complaints. PTSD has been observed in solders returning from combat operations, eliciting the typical triad of hippocampal complaints: headache, cognitive, and hypersensitivity. We theorized that because of the favorable results reported with EMDR Therapy in persons with PTSD, which incorporates visual and auditory movements, that persons with hydrocephalus might respond favorably to rhythmic auditory therapies.

Our Three-Fold Study Goal Encompassed:

1. To determine whether there is an association between chronic complaints (common in hydrocephalus) to central vestibular deficit with visual gaze dependency; and

2. To determine if there is an association between type of auditory rhythmic pattern, and exacerbation of sensory processing complaints and sensitivities; and

3. To observe whether vestibular, auditory, and visual therapies might prove effective in strengthening the neuro-compensatory mechanism, and reduce levels of headache, neuro-hypersensitivity, and/or neuro-cognitive complaints.

MATERIALS: 1. Airex balance mat; 2. Standardized vestibular test and therapeutic protocol; 3. Standard business card attached to an 18 inch wooden bar. 4. Boss 64 track recording system with built in "metronome," having "50" selectable rhythm patterns, volume, and tempo controls; 5. Pen and paper used to identify each of the "50" rhythms, and note study subject responses to each, with volume and tempo variations; 6. Audio-cassette recorder and (2) blank cassette tapes; 7. Several cassette tapes containing soft music; and 8. Yamaha keyboard.

METHODS: Using the Airex balance mat, vestibular testing was undertaken on a group of (16) persons: (8) patients with shunted hydrocephalus (N=8), and (8) persons as normal control subjects. The study group was screened for visual dependency, and then interviewed briefly regarding specific nature and frequency of common hydrocephalus complaints (HA, neuro-hypersensitivity, vestibular changes). Each study subjectís vestibular system was challenged while on the Airex mat, first with eyes open, then with eyes closed. A third test then employed a moving business card, moving laterally to and fro, where the subjects were asked to focus on the moving target and maintain their balance.

The auditory protocol exposed three (3) study subjects to our protocol. One had a diagnosis of hydrocephalus, and the other two had diagnoses of developmental disorders. All three (3) reported complaints consistent with neuro-hypersensitivities. We used a Boss recorder to generate a total of fifty (50) metronome patterns, where tempo and volume level were both varied on each rhythm. We painstakingly evaluated and categorized specific rhythms prior to the study, so we could better introduce them later in the study. Initially, we randomly picked rhythms until we began to see a pattern emerge with the type, complexity, and tempo of the rhythms while we asked the study subjects to describe their "degree" of both adverse or favorable responses via sensations of neuro hypersensitivity complaints. We then varied the volume and tempo. We identified (12) twelve rhythms which produced the strongest increase in complaints, and a few that were found to produce a therapeutic "relief" in complaints. We wanted to identify a select group of most problematic rhythms so as to create a "therapeutic audio- tape" of patterns, to play at small intervals to minimize hypersensitivity. We felt we could increase the study subjects tolerance and compensatory adjustment to these patterns. We then evaluated the study subjects responses to a full range of tones/notes using a Yamaha keyboard, and additionally evaluated their responses when these tones were combined with the previously selected rhythms from the metronome.

RESULTS AND DISCUSSION: Sensory processing disorders, or SPDs, are often associated with vestibular deficit, hearing and/or processing difficulties, headaches, visual deficits, neuro-hypersensitivities, and neuro-cognitive deficits. Some of these deficits can be associated with changes in ICP and CBF. Multiple Sclerosis, Parkinson's Disease, and dementia can also exhibit many of these same features. Developmental disorders and autism can be associated with neuro hypersensitivities as well.

In this study, participants with hydrocephalus who were unable to maintain balance on the Airex mat with their eyes closed, or follow a moving visual target such as a business card without loosing balance, also reported a more problematic level of the triad of chronic hydrocephalus complaints. Those who failed the eyes closed test, also failed the moving target test. Those who tested normal in the vestibular challenge tests, interestingly reported a lesser degree of chronic triad complaints, especially headache. This latter group's "normal" vestibular findings were roughly identical to the control (normal) group. Our findings were also age independent, rather, there were no significant differences in results with age, though no participants were older than 50 years of age. Those in the study ranged between the age of 7 and 50 years of age, and were equally divided in the respective visual-dependant vestibular, normal vestibular, and control subjects. 

For the auditory stimuli segment of our study, we first evaluated (50) auditory tones of the Boss metronome machine to identify and group rhythm patterns. We postulated that we might be able to use selected rhythms to create a therapeutic audiotape that could gradually de-sensitize study subjects, increase compensatory action, and reduce auditory neuro-hypersensitivities.

We identified (12) metronome patterns which produced complaints in the study subjects. The complaints appeared to be less related to volume, but just slightly related to tempo. This response also varied slightly with the different rhythms. We then narrowed the rhythms down to (6) problematic non-rhythmic patterns, which produced intolerable complaints in all three (3) study subjects within a 10 second interval. This response was also related to the status of the study subject prior to initiating the auditory test exposure: the more rested the study subject, the slightly more he/she tolerated the sound. The most critical discovery was the (6) patterns that consistently produced an adverse response, while a number of others seemed to provide relief in complaints.

We observed (8) to (10) of the rhythms appeared to relax the subjects. From here, we identified (3) three that were the most pleasing. We postulated that the adverse response to the most (repetitive) metronome patterns, and also faster tempos, was due to processing deficits, inflammation, injury, and/or atrophy of the sensory processing centers, and exacerbated today by the abundance of non-rhythmic auditory sounds in everyday life, albeit from machinery, crowded public places, and the prevalence of modern audio-visual equipment. Such repetitive rhythms creates more difficult prospects for an affected person to assimilate and compensate. We also postulate that the (abnormal) study responses indicate persons who are unable to compensate to these stimuli under ordinary circumstances, and thus suffer more problematic cognitive, headache, irritability, etc. sensory complaints.

We next created an audiotape combining both the identified pleasing and offensive rhythms, and others with different keyboard tones, and still other tracks with soft music as a music therapy reference standard. We then evaluated three (3) study subjects known to experience neuro-hypersensitivities with the auditory therapy tapes. All three (3) reported a 30% or more decrease in severity of sensory processing complaints with the pleasing rhythms.

We also informally interviewed between 10 and 20 individuals, with varying etiologies of neurological disorder and injury, and were consistently informed that each suffered the most offensive responses to "repetitive" rhythms from a variety of sources, notably, jackhammer guns, truck and diesel engines, and the beeping sound of forklifts and trucks when backing up.

It is unclear which sound therapy tracks on the tape contributed most to the reduction in chronic complaints, as the study did not allow for separate measurements. What was of importance, though, was that it did help to de-sensitize those who were at risk for adverse response to non-rhythmic auditory stimuli. We also postulate these chronic neurological complaints may be related to deficits within the hippocampus. It would be helpful to have corroboration with fMRI or PET imaging for further clarification.

In closing, it would appear this study demonstrated sufficient favorable findings to pursue a larger formalized study, including corroboration using fMRI or PET imaging. We also believe vestibular and audible rhythm therapies are helpful in reducing mild to moderate sensory overload complaints in children and adults suffering from a variety of sensory processing and neurological disorders, and that it might be put in place in noisy classroom and industrial settings. Auditory and vestibular therapies may also aid chronic "seizure activity" related to dysfunction of the hippocampus.

We now feature a more recent slide show by Stephen Dolle on our home page, entitled "Group Drumming: Engaging the Rhythms of your Brain," from his keynote on drumming methodologies in STEM3, at Wright State University in Dayton, Ohio, on October 5, 2011.

Click to also listen/download this healing instrumental song Stephen wrote as a hydrocephalus survivor in 1996: "Evening Solstace."

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4. AI Technology

5. Hydrocephalus

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