El refuerzo Los materiales compuestos tipo PVC-fibras naturales

The North Surrey branch of the Multiple Sclerosis Society was contacted and members who were willing to have their voices taped and answer questions were approached. It was stressed that there was no need to have a speech problem to be part of the study. Nine individuals were visited in their homes at a time chosen by the subject. In this way it was hoped to avoid times of excessive fatigue that were predictable to the subject. All subjects were seen within a fortnight of each other.

Two men and seven women volunteered which is not representative of the multiple sclerosis population where women are affected more often than men at a ratio of 3:2 (Mathews et al. 1985). The average age of the women in this sample was 60.1 years with a range of 47 to 70 years. The two men were aged 49 and 55 giving a mean of 53 years. The average time since onset of MS was 19.1 years with a range from 13 to 30 years. None of the subjects had a history of speech or voice difficulties before the diagnosis of MS such as thyroid problems, anaemia, hormone treatment, stroke, stuttering or organic or psychogenic voice problems. No subject had undergone cortico-steroid treatment for their MS in the last 18 months:

Subject Age

Age at

Diagnosis UEF^ Activity

K raft

Mobility^ Resides Sex

A 68 38 7 Little 5 Home F

B 52 22 L6

R 1

None 4 Home F

C 70 55 6 Walks twice daily 3 Home F

D 62 46 7 None 5 Home F

E 55 40 6-7 Swimming & Walking 2 Home M

F 56 39 2 Yoga once per week 5 Home F

G 66 50 6 Physiotherapy twice weekly 4 Home F

H 47 28 1 None 6-7 Home F

1 49 36 None 3-4 Home M

• See A ppendix A for details o f the U pper E xtrem ity Function and K raft IV obility

Figure 7: Laryngograph Study Participants Profile

3.2.1.3 Data Collection In The Laryngograph Study

A voice history of the subject was taken and the subject’s own perception of his voice and speech questioned. The researcher classified the subject’s speech during the course of the interview from pre-determined criteria into one of four categories: speech was perceptually normal showing no signs of dysarthria (Normal); there were beginning to be signs of difficulties with speech probably most apparent when the subject was tired, during extended use of voice or on the telephone (Early Indications); dysarthria was apparent during conversation (Established); and finally speech was deviant enough to affect intelligibility (Intelligibility Affected).

There was no attempt to rank order subjects, simply to assign them to these

mutually exclusive “stages” in the dysarthria. This scale is not unlike the

Amyotrophic Lateral Sclerosis (ALS) Severity Scale-Speech (Hillel et al. 1989). Hillel’s is a 10 point scale divided into 5 sections, normal speech processes, detectable speech disturbance, behavioural modifications, use of augmentative communication and loss of useful speech:

Rating___________________________________ Description NORMAL SPEECH PROCESSES

10 Normal Speech: Individual denies any difficulty speaking. Examination demonstrates no

abnormality

9 Nominal Speech Abnorm ality: Only the individual with ALS or spouse notices that

speech has changed. Maintains normal rate and volume. DETECTABLE SPEECH DISTURBANCE

8 Perceived Speech Changes: Speech changes are noted by others, especially during

fatigue or stress. Rate of speech remains essentially normal.

7 Obvious Speech Abnormalities: Speech is consistently impaired. Affected are rate,

articulation, and resonance. Remains easily understood. BEHAVIORAL MODIFICATIONS

6 Repeats Messages on Occasion: Rate is much slower. Repeats specific words in adverse

listening situations. Does not limit complexity or length of message.

5 Frequent R epeating Required: Speech is slow and labored. Extensive repetition or a

“translator” is commonly needed. Person probably limits the complexity or length of messages.

USE O F AUGMENTATIVE COMMUNICATION

4 Speech Plus Augmentative Communication: Speech is used in response to questions.

Intelligibility problems need to be resolved by writing or a spokesperson.

3 Limits Speech to One-W ord Response: Vocalizes one-word response beyond yes/no;

otherwise writes or uses a spokesperson. Initiates communication nonvocally. LOSS OF USEFUL SPEECH

2 Vocalizes for Emotional Expression: Uses vocal inflection to express emotion,

affirmation, and negation.

1 Nonvocal: Vocalization is effortful, limited in duration, and rarely attempted. May

vocalize for crying or pain.

X Tracheostomy

Figure 8: HillePs Ranking of Speech in ALS (Hillel et al. 1989)

The Normal group in this study, includes the ALS rating of 10 and 9; the Early Indications group is equivalent to ALS rating scale 8; ratings 7 and 6 correspond to the Established Dysarthria group. Rating 5, the last level of verbal speech on the ALS scale, is parallel to the Intelligibility Affected group. Hillel reports little difficulty with allocating subjects into these mutually exclusive groups.

A complete laryngographic assessment was performed on all subjects at both

G(x) (gross low frequency larynx movement) and normal frequency filter settings on

the portable laryngograph 'with custom made gold plated electrodes, both supplied by Laryngograph Ltd. A Thandar HOC oscilloscope was used to ensure the strongest signal was elicited and maintained during the taping. Voice was also taped using a boom microphone stand with a R249-946 Dynamic microphone placed at a mouth to

microphone distance of 8 inches. While the boom microphone is more obtrusive than a lapel clip microphone it was found to be optimal for controlling mouth-to- microphone distance and maintaining the strongest signal for weakened subjects in

wheelchairs. One subject remained very conscious of the recording equipment

exhibiting very controlled speech (Subject E) but the others soon habituated to it. Data was recorded on a Marantz Model C230 tape recorder using TDK premium lEClV tapes. Gain was adjusted initially to 0 and was monitored but not adjusted again during the recording. All recording was carried out using battery power not

mains power to avoid AC frequency interference. Sustained vowels /a/, /i/ and /u/

and two phonetically balanced standard reading passages were taped during which time checklists of respiratory patterns and voice quality were completed. Finally the subject was engaged in conversation until about 4 minutes of spontaneous speech was collected. Two minutes into the conversation the gain was switched and the entire laryngographic sample was retaken at the new gain. Half the subjects were taken with

Q(x) first and half with normal gain first. G(x) refers to gross low frequency larynx movement that the laryngograph usually filters out since it is the variation in conductance due to features other than vocal cord closure, such as larynx elevation.

However with MS it was hypothesised that the G(x) might show consistent

abnormalities by showing an increase in this lower frequency behaviour as the dysarthria progressed or may show a consistent abnormality in the individual waveforms obtained from vowel prolongation both at the time of initiation of phonation or just before.

Finally a motor speech examination was performed consisting of standard respiratory and phonatory tasks, diadochokinetic rates and the Frenchay Dysarthria

Assessment Section 8, Intelligibility. The tasks included in the assessment can be classified according to the “level” of the speech system they were targeting:

Speech level Task

Articulation: Diadochokinesis /pV, /tV, /Tca/, /pAtAkA/

Resonance: Air escape on held breath (nasal or oral) /m/ Pol alternation

Phonation: Sing scale - on own or matching given pitch Imitate pitch patterns

Cough, clear throat

Observation of voice quality and register /s/:/z/ ratio

Respiration: Count on maximum inhalation Observation of breathing pattern Vary loudness

Observation of habitual loudness Maximum Phonation Time

During each examination the researcher sat a table comer width away from the subject to allow good posture and head position relative to the microphone to be maintained and to allow a fairly standard and not large, intervening space for voice projection. Motor speech tasks were explained and demonstrated before the subject attempted the task. Subsequent attempts were allowed if either the researcher or the subject wished it, usually when it was thought that a better performance might be elicited or, as with MPT, there might be a practice effect.