[Dysphagia] Silent aspiration

[Paula.Leslie at newcastle.ac.uk (Paula leslie)]

Thanks Lynne

Our paper was looking at rater agreement within and between raters and then 
with VF.  We never asked people to say if it was aspiration or not but just 
abnormal/normal swallow sounds.  In trials people were often reluctant to say 
if it was a definite thing like aspiration, but were prepared to say if it was 
a bit odd sounding ie abnormal.  We had to choose aspiration/penetration as 
the defining feature as there are very few "objective" things that can be 
rated on VF in CA studies.

Specificity was 66% and sensitivity was 62%, a bit better than chance but not 
significantly better than a clinical exam.  That is, individuals were not very 
good at spotting aspiration/penetration.  Interestingly when the group 
consensus was considered this improved to 90% and 80% respectively.  This 
suggests that there might be something in the sounds but you need to get a big 
group of people to listen and we don't tend to do that on the wards.  This 
still does not give us evidence that people can spot aspiration, just 
something "abnormal".  We need to do another study.

The Cichero study:

>===== Original Message From Lynne <nprw@xmission.com> =====
>Another abstract:
>
>Dysphagia. 2002 Winter;17(1):40-9. Related Articles, Links
>
>Detection of swallowing sounds: methodology revisited.
>
>Cichero JA, Murdoch BE.
>
>Department of Speech Pathology and Audiology, University of Queensland,
>Brisbane, Australia
>
>Cervical auscultation is in the process of gaining clinical credibility.
>In order for it to be accepted by the clinical community, the procedure
>and equipment used must first be standardized. Takahashi et al.
>[Dysphagia 9:54-62, 1994] attempted to provide benchmark methodology for
>administering cervical auscultation. They provided information about the
>acoustic detector unit best suited to picking up swallowing sounds and
>the best cervical site to place it. The current investigation provides
>contrasting results to Takahashi et al. with respect to the best type of
>acoustic detector unit to use for detecting swallowing sounds. Our study
>advocates an electret microphone as opposed to an accelerometer for
>recording swallowing sounds. However, we agree on the optimal placement
>site. We conclude that cervical auscultation is within reach of the
>average dysphagia clinic.


This paper is looking at recording methodology and did not use simultaneous VF 
or LSE, the authors state that simultaneous studies are needed.  It studied 10 
non neurologically impaired people with no history of swallowing disorders - a 
group unlikely to aspirate according to the literature available.  Unless I 
have misread their paper it does not address the issue of aspiration sounds at 
all.

We've all heard sounds that might be material trickling into the trachea, but 
that's all we can say, "might be" unless we have them validated against a gold 
standard and for that we need the imaging.  We over estimate the presence of 
aspiration when people don't aspirate (Stroud, 2002).

We have studied cervical auscultation and recording of swallow sounds 
simultaneously with both laryngeal and videofluoroscopic swallow studies and 
this data is awaiting publication.

I can only presume that because of the number of people who are quite adamant 
that they can definitely  hear aspiration etc they must be doing this with an 
imaging system.  This is exactly what we need in the literature - let's hope 
more is published.

Paula


===== Original Message From Lynne <nprw@xmission.com> =====
>Here is an abstract from pubmed.com.
>
>http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?
cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15667057&itool=iconabstr&query_
hl=2
><http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?
cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15667057&itool=iconabstr&query_
hl=2>
>
>Dysphagia. 2004 Fall;19(4):231-40. Related Articles, Links
>
>Reliability and validity of cervical auscultation: a controlled
>comparison using videofluoroscopy.
>
>Leslie P, Drinnan MJ, Finn P, Ford GA, Wilson JA.
>
>School of Surgical and Reproductive Sciences, The Medical School,
>University of Newcastle, Newcastle-upon-Tyne, United Kingdom.
>Paula.Leslie@newcastle.ac.uk
>
>Cervical auscultation is experiencing a renaissance as an adjunct to the
>clinical swallowing assessment. It is a controversial technique with a
>small evidence base. We have aimed to establish whether cervical
>auscultation interpretation is based on the actual sounds heard or, in
>practice, influenced by information gleaned from other aspects of the
>clinical assessment, medical notes, or previous knowledge. We sought to
>determine (a) rater reliability and its impact on the clinical value of
>cervical auscultation and (b) how judgments compare with the "gold
>standard": videofluoroscopy. Swallow sounds were computer recorded via a
>Littmann stethoscope. Sounds were sampled from 10 healthy control
>swallows with no aspiration/penetration and 10 patient swallows with
>aspiration/penetration, all recorded during simultaneous
>videofluoroscopy. The system generated sound quality similar to "live"
>bedside listening, a feature rarely seen in cervical auscultation
>studies. The 20 sound clips were classified as "normal" or "abnormal" by
>19 volunteer speech-language pathologists with experience in cervical
>auscultation. After at least four weeks, 11 of these judges rated the
>sounds rerandomized on a new CD. Intrarater reliability kappa ranged
>from -0.12 to 0.71. Individual reliability did not correlate with years
>of experience, practice pattern, or frequency of use. Interrater
>reliability kappa = 0.17. Comparison with radiologically defined
>aspiration/penetration yielded 66% specificity, 62% sensitivity, and
>majority consensus gave 90% specificity, 80% sensitivity. There was a
>significant relationship between individual reliability and true
>positive rate (r(s) = 0.623, p = 0.040). The reliability of individual
>judges varied widely and thus, inevitably, agreement between judges was
>poor. Validity is dependent upon reliability: Improving the poor raters
>would improve the overall accuracy of this technique in predicting
>abnormality in swallowing. The group consensus correctly identified 17
>of the 20 clips so we may speculate that the swallow sound contains
>audible cues that should in principle permit reliable classification.
>
>Lynne
>
>Paula leslie wrote:
>
>>I am curious about how exactly CA allows one to detect "silent aspiration"
>>when, to my knowledge, there is no evidence that shows aspiration (silent or
>>otherwise) linked to any sound made before, during or after swallowing.  We
>>need videofluoroscopy or laryngoscopy images ie direct visualisation done on
>>the same swallow not just the same patient at a different time.  Anything 
else
>>is just presumption of a link.  People do talk of wet breath sounds but 
again
>>there is no evidence of what exactly this is.
>>
>>Features such as coughing, wet voice, stridor etc do not need CA to be
>>detected.
>>
>>People may have such data from simultaneous swallow studies, ie CA AND 
VF/LSE
>>done at the same time.  If so it would be very useful to get them into the
>>public domain to increase the evidence base on this topic.
>>
>>Paula
>>
>>
>>
>>
>>
>>
>>
>>>===== Original Message From Kimberley ODonnell
>>>
>>>
>><OdonneK@doh.health.nsw.gov.au> =====
>>
>>
>>>I agree that cervical auscultation is extremely useful in detecting
>>>silent aspiration in many but not all people.   Wouldn't be without it.
>>>Kim
>>>
>>>Kimberley O'Donnell
>>>Speech Pathologist - BAppSc MSPAA CPSP
>>>Royal Rehab. Centre Sydney
>>>ph:(02) 9808 9210 or (02) 9807 1144 - pager 48
>>>59 Charles Street   RYDE   NSW 2112
>>>
>>>
>>>
>>>>Pat Buen <patbuen@telus.net> 10/11/2005 2:56:15 pm >>>
>>>>
>>>>
>>>As Debbie states, however my last bedside test (b/4 VFSS if needed)
>>>includes
>>>cervical auscultation and a good assessment of  lung status.
>>>Pat
>>>----- Original Message -----
>>>From: <LCDM11@aol.com>
>>>To: <tervomm@yahoo.com>; <dysphagia@b9.com>
>>>Sent: Wednesday, November 09, 2005 7:38 PM
>>>Subject: Re: [Dysphagia] Silent aspiration
>>>
>>>
>>>
>>>
>>>It's SILENT aspiration. It can't be determined at bedside. You may
>>>
>>>
>>>have
>>>
>>>
>>>reason to suspect it, but it CAN NOT be determined by a clinical
>>>
>>>
>>>evaluation.
>>>
>>>
>>>Debbie
>>>_______________________________________________
>>>Dysphagia mailing list
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>>>
>>>
>>
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>
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