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Equating scores of the University of Pennsylvania Smell Identification Test and Sniffin' Sticks test in patients with Parkinson's disease

Lawton, Michael; Hu, Michele T M; Baig, Fahd; Ruffmann, Claudio; Barron, Eilidh; Swallow, Diane M A; Malek, Naveed; Grosset, Katherine A; Bajaj, Nin and Barker, Roger A LU , et al. (2016) In Parkinsonism and Related Disorders 33. p.96-101
Abstract

BACKGROUND: Impaired olfaction is an important feature in Parkinson's disease (PD) and other neurological diseases. A variety of smell identification tests exist such as "Sniffin' Sticks" and the University of Pennsylvania Smell Identification Test (UPSIT). An important part of research is being able to replicate findings or combining studies in a meta-analysis. This is difficult if olfaction has been measured using different metrics. We present conversion methods between the: UPSIT, Sniffin' 16, and Brief-SIT (B-SIT); and Sniffin' 12 and Sniffin' 16 odour identification tests.

METHODS: We used two incident cohorts of patients with PD who were tested with either the Sniffin' 16 (n = 1131) or UPSIT (n = 980) and a validation... (More)

BACKGROUND: Impaired olfaction is an important feature in Parkinson's disease (PD) and other neurological diseases. A variety of smell identification tests exist such as "Sniffin' Sticks" and the University of Pennsylvania Smell Identification Test (UPSIT). An important part of research is being able to replicate findings or combining studies in a meta-analysis. This is difficult if olfaction has been measured using different metrics. We present conversion methods between the: UPSIT, Sniffin' 16, and Brief-SIT (B-SIT); and Sniffin' 12 and Sniffin' 16 odour identification tests.

METHODS: We used two incident cohorts of patients with PD who were tested with either the Sniffin' 16 (n = 1131) or UPSIT (n = 980) and a validation dataset of 128 individuals who took both tests. We used the equipercentile and Item Response Theory (IRT) methods to equate the olfaction scales.

RESULTS: The equipercentile conversion suggested some bias between UPSIT and Sniffin' 16 tests across the two groups. The IRT method shows very good characteristics between the true and converted Sniffin' 16 (delta mean = 0.14, median = 0) based on UPSIT. The equipercentile conversion between the Sniffin' 12 and 16 item worked well (delta mean = 0.01, median = 0). The UPSIT to B-SIT conversion showed evidence of bias but amongst PD cases worked well (mean delta = -0.08, median = 0).

CONCLUSION: We have demonstrated that one can convert UPSIT to B-SIT or Sniffin' 16, and Sniffin' 12 to 16 scores in a valid way. This can facilitate direct comparison between tests aiding future collaborative analyses and evidence synthesis.

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publishing date
type
Contribution to journal
publication status
published
in
Parkinsonism and Related Disorders
volume
33
pages
96 - 101
publisher
Elsevier
external identifiers
  • scopus:84992195169
ISSN
1873-5126
DOI
10.1016/j.parkreldis.2016.09.023
language
English
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no
id
e119d0cc-fd4f-432a-95a3-372994635d5d
date added to LUP
2016-11-23 13:02:57
date last changed
2017-08-27 06:29:42
@article{e119d0cc-fd4f-432a-95a3-372994635d5d,
  abstract     = {<p>BACKGROUND: Impaired olfaction is an important feature in Parkinson's disease (PD) and other neurological diseases. A variety of smell identification tests exist such as "Sniffin' Sticks" and the University of Pennsylvania Smell Identification Test (UPSIT). An important part of research is being able to replicate findings or combining studies in a meta-analysis. This is difficult if olfaction has been measured using different metrics. We present conversion methods between the: UPSIT, Sniffin' 16, and Brief-SIT (B-SIT); and Sniffin' 12 and Sniffin' 16 odour identification tests.</p><p>METHODS: We used two incident cohorts of patients with PD who were tested with either the Sniffin' 16 (n = 1131) or UPSIT (n = 980) and a validation dataset of 128 individuals who took both tests. We used the equipercentile and Item Response Theory (IRT) methods to equate the olfaction scales.</p><p>RESULTS: The equipercentile conversion suggested some bias between UPSIT and Sniffin' 16 tests across the two groups. The IRT method shows very good characteristics between the true and converted Sniffin' 16 (delta mean = 0.14, median = 0) based on UPSIT. The equipercentile conversion between the Sniffin' 12 and 16 item worked well (delta mean = 0.01, median = 0). The UPSIT to B-SIT conversion showed evidence of bias but amongst PD cases worked well (mean delta = -0.08, median = 0).</p><p>CONCLUSION: We have demonstrated that one can convert UPSIT to B-SIT or Sniffin' 16, and Sniffin' 12 to 16 scores in a valid way. This can facilitate direct comparison between tests aiding future collaborative analyses and evidence synthesis.</p>},
  author       = {Lawton, Michael and Hu, Michele T M and Baig, Fahd and Ruffmann, Claudio and Barron, Eilidh and Swallow, Diane M A and Malek, Naveed and Grosset, Katherine A and Bajaj, Nin and Barker, Roger A and Williams, Nigel and Burn, David J and Foltynie, Thomas and Morris, Huw R and Wood, Nicholas W and May, Margaret T and Grosset, Donald G and Ben-Shlomo, Yoav},
  issn         = {1873-5126},
  language     = {eng},
  month        = {09},
  pages        = {96--101},
  publisher    = {Elsevier},
  series       = {Parkinsonism and Related Disorders},
  title        = {Equating scores of the University of Pennsylvania Smell Identification Test and Sniffin' Sticks test in patients with Parkinson's disease},
  url          = {http://dx.doi.org/10.1016/j.parkreldis.2016.09.023},
  volume       = {33},
  year         = {2016},
}