Abstract
Purpose
The aim of the study was to identify alterations in the auditory processing of patients with chronic cerebellar disease using a dichotic listening test with alternating dissyllables, also known as the Staggered Spondaic Word (SSW) test.
Materials and methods
A study involving a control group of 20 subjects and a study group of 18 patients with chronic cerebellar disease of both sexes aged between 9 and 56 years was performed. The SSW test was conducted in accordance with strict standard protocols along with the analysis procedures.
Results
Findings revealed a statistically significant difference in the quantitative alterations on the SSW test in the study group compared with the control group ( P < .001). Results of the qualitative evaluation showed no statistically significant differences between the study and control groups for order or auditory effects. However, a statistically significant difference for presence of inversions was identified, with the worse result in the study group.
Conclusion
The present study identified quantitative and qualitative changes in auditory processing for decodifying, gradual memory loss, and organization modes on the dichotic listening test with alternating dissyllables (SSW) in individuals with chronic cerebellar disease.
1
Introduction
For many years, the cerebellum was thought to be a nervous system structure responsible solely for motor coordination and balance. However, recent research has investigated and confirmed its role in modulating cognitive functions in both animals and humans. The cerebellum is located in the posterior part of the central nervous system, constituting about 10% of its volume. It thus gained the Latin name “cerebellum,” meaning “little brain,” and contains more than 50% of the central nervous system neurons .
Numerous studies in neuroscience coupled with several noninvasive imaging examinations available have enabled researchers to “see what we are doing.” Functional magnetic resonance imaging, for instance, monitors the regional changes in blood oxygenation during neuronal activity , whereas positron emission tomography allows qualitative and quantitative assessments of the functional brain based on changes in cerebral blood flow. These techniques have revealed that the cerebellum is responsible for many other functions besides coordination and balance, such as involvement in cognition and auditory perception.
Neuroanatomy studies indicate a functional relationship between the cerebral cortex and cerebellum, showing that cognitive changes observed actually stem from, or are modulated by, cerebellar structures .
Using neuroimaging techniques, some authors have shown cerebellar activation across a wide variety of perceptive and cognitive activities, such as timing , language production, and comprehension as well as visual attention . These functions are indispensable for auditory processing.
Auditory processing involves not only perception of sounds but also how they are identified, located, brought to attention, analyzed, memorized, and retrieved from auditory memory.
The “Staggered Spondaic Word” (SSW) test for disyllabic recognition is based on a dichotic task devised by Katz in 1962 and assesses binaural synthesis and auditory integration . It is a straightforward, easy-to-apply test for identifying individuals with auditory pathway dysfunction.
In translating the test into Portuguese in 1986, Borges sought to select vocabulary, ensuring that the Portuguese version reflected the original in English as closely as possible, despite that spondaic words are not as common in Brazilian Portuguese as in English.
The aim of the present study was to identify changes in auditory processing in individuals with chronic cerebellum disorders using the dichotic listening alternating dissyllable test (SSW in the Portuguese version).
2
Casuistic and methods
This research project (376/05) was approved by the institutional research ethics committee, with registration at the Sistema Nacional de Informações sobre Ética em Pesquisa/ Ministério da Saúde (National Information System on Research Ethics / Ministry of Health) under the number Certificado de apresentação para apreciação em ética (Certificate of appreciation for presentation in ethics) 0009.0.270.000-05.
A total of 38 patients were assessed comprising 20 subjects with no auditory problems or history of neurologic changes (control group) and 18 patients diagnosed with chronic cerebellum disorder recruited from the Neurology and Neurosurgery Service of the Irmandade da Santa Casa de Misericórdia de São Paulo, who met the study inclusion criteria (study group). For the purposes of this study, chronic disease was defined as permanent, with residual disability, caused by irreversible pathologic change, and requiring special training of the individual for rehabilitation or a long expected period of supervision, care, or observation.
All participants from both groups were given clear and objective explanations about the study goals as well as information on the examinations to which they would be submitted. Those who agreed to take part signed a free and informed consent form.
Both groups were assessed and submitted to audiological tests from July 2005 to May 2007. Data were compiled using an attendance protocol that included anamnesis and audiological examinations for all individuals in addition to neurologic and imaging examinations for patients in the study group.
All tests were performed by the same speech therapist, with tests administered to all individuals in the same order, the results of which were recorded on an assessment form.
Inclusion criteria for both groups are as follows:
- 1.
Absence of history of otological disorders, exposure to loud noises, ototoxic drugs, and no family history of hearing deficits and patients testing positive for any of these were excluded.
- 2.
Patients with hearing thresholds of up to 25 dB nivel de audição (level of hearing) at the frequencies of 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz within normal limits and monosyllable discrimination greater than 88%.
- 3.
Tympanometric curve with a peak pressure between +100 and −100 of the pascal, that is, type A.
Specific inclusion criteria for individuals of the study group stipulated that the patients should have a clinically diagnosed chronic cerebellar disorder confirmed on imaging studies ( Tables 1 and 2 ) and should have no lesions to other segments of the central nervous system.
| Case | Age | Sex | Side | Disease | Time/evolution | Treatment | Surgery | Sequelae |
|---|---|---|---|---|---|---|---|---|
| 1 | 55 | M | L | Cerebellar ischemic stroke sequelae | 2 y | Physiotherapy | No | Gait and speech |
| 2 | 9 | M | R | Tumor of cerebellum | 2 y | Hemispheric cerebellar surg | January 9, 2000 | Worse handwriting |
| 3 | 32 | F | R | Congenital malformation. Arachnoid cyst of cerebellopontine angle cistern | Congenital | No | No | Vertigo crisis |
| 4 | 43 | F | R | Hemangioblastoma | September 6, 2006 | No | September 6, 2006 | Difficulties in memory and speech comprehension |
| 5 | 23 | F | All | Cerebellar ataxia. Asymmetry of cerebellar hemispheres with enlarged sulci. | 7 y | Physiotherapy | No | Change in gait and fine motor movements |
| 6 | 21 | M | All | Cerebellar degeneration. Diffuse atrophy of the cerebellum. | 4 y | Physiotherapy | No | Gait and speech problems |
| 7 | 45 | F | Central (interhemispheric) | Arteriovenous malformation, cerebellar | 2003 | Surgery | 2003 | None |
| 8 | 47 | M | L | Meduloblastoma of the cerebellum | 2005 | Surgery + radiotherapy and chemotherapy | 2005 | Dizziness |
| 9 | 56 | M | All | Spinocerebellar ataxia | 5 y | Clinical | No | Swallowing, choking, diplopia, handwriting |
| Case | Age | Sex | Side | Disease | Time/evolution | Treatment | Surgery | Sequelae |
|---|---|---|---|---|---|---|---|---|
| 10 | 54 | M | All | Spinocerebellar ataxia | 9 y | Clinical | No | Gait |
| 11 | 34 | M | R | Hemangioblastoma | 2 y | Surgery | June 1, 2007 | None |
| 12 | 30 | M | L | Meduloblastoma | 2 y | Surgery | September 2, 2007 | Change in balance to left |
| 13 | 43 | M | L | Cerebellar ataxia. Sequelae ischemic stroke occlusion L vertebral artery. | 3 y | Clinical | No | Gait difficulties |
| 14 | 21 | M | R + bi | Tumor of cerebellum. Hemisphere gliosis. R cerebellum + bulb | 9 y | Surgery, physiotherapy and radiotherapy | First 2001 and last 2005 | Balance and R paresis |
| 15 | 35 | F | L | Hemangioblastoma | 3 y | Surgery | 2004 | None |
| 16 | 33 | F | L | Cerebellar astrocytoma | 6 y | Surgery | 2001 | Gait and vision |
| 17 | 23 | F | R | Cerebellar ischemic stroke sequelae | 3 y | No | No | Balance and R paresis |
| 18 | 30 | M | R | Hemangioblastoma | 4 y | Surgery | 2003 | None |
In both groups, tests were conducted to calculate auditory threshold and imitanciometry measurements. A basic auditory assessment was performed by tone threshold audiometry and vocal discrimination, including speech intelligibility and vocal discrimination thresholds, using an Itera type audiometer (Madsen). Imitanciometry encompassed tympanometry, assessment of the threshold of the ipsi, and contralateral reflex of the stapedius muscle at 500, 1000, 2000, and 4000 Hz using a Madsen ZS77-MB device.
2.1
The SSW test
The SSW test was conducted in a soundproof booth with phonetic messages introduced through earphones. The message was produced using a compact CD device coupled with a 2-channel ITERA audiometer.
The dichotic alternating dissyllable test (SSW) was administered to both groups. A total of 40 items were presented. Each item comprised 4 words (2 pairs of paroxytone disyllabic words) presented at 50 decibel nível de sensação (decibel level of sensation)—the first word was presented in 1 ear (eg, the right) under noncompetitive conditions, the second and third were presented in both ears under competitive conditions (second and third words partially overlapping), and the fourth word was presented in the other ear (eg, left) under noncompetitive conditions. The subsequent sequence was started in the opposite ear with the words presented in the same manner as in the first sequence. The individual had to repeat the words in the order presented.
2
Casuistic and methods
This research project (376/05) was approved by the institutional research ethics committee, with registration at the Sistema Nacional de Informações sobre Ética em Pesquisa/ Ministério da Saúde (National Information System on Research Ethics / Ministry of Health) under the number Certificado de apresentação para apreciação em ética (Certificate of appreciation for presentation in ethics) 0009.0.270.000-05.
A total of 38 patients were assessed comprising 20 subjects with no auditory problems or history of neurologic changes (control group) and 18 patients diagnosed with chronic cerebellum disorder recruited from the Neurology and Neurosurgery Service of the Irmandade da Santa Casa de Misericórdia de São Paulo, who met the study inclusion criteria (study group). For the purposes of this study, chronic disease was defined as permanent, with residual disability, caused by irreversible pathologic change, and requiring special training of the individual for rehabilitation or a long expected period of supervision, care, or observation.
All participants from both groups were given clear and objective explanations about the study goals as well as information on the examinations to which they would be submitted. Those who agreed to take part signed a free and informed consent form.
Both groups were assessed and submitted to audiological tests from July 2005 to May 2007. Data were compiled using an attendance protocol that included anamnesis and audiological examinations for all individuals in addition to neurologic and imaging examinations for patients in the study group.
All tests were performed by the same speech therapist, with tests administered to all individuals in the same order, the results of which were recorded on an assessment form.
Inclusion criteria for both groups are as follows:
- 1.
Absence of history of otological disorders, exposure to loud noises, ototoxic drugs, and no family history of hearing deficits and patients testing positive for any of these were excluded.
- 2.
Patients with hearing thresholds of up to 25 dB nivel de audição (level of hearing) at the frequencies of 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz within normal limits and monosyllable discrimination greater than 88%.
- 3.
Tympanometric curve with a peak pressure between +100 and −100 of the pascal, that is, type A.
Specific inclusion criteria for individuals of the study group stipulated that the patients should have a clinically diagnosed chronic cerebellar disorder confirmed on imaging studies ( Tables 1 and 2 ) and should have no lesions to other segments of the central nervous system.
