/memr

R package for Multisource Embeddings for Medical Records

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memr

Medical records embeddings

The memr(Multisource Embeddings for Medical Records) package in R allows for creating embeddings, i.e. vector representations, of medical free-text records written by doctors. It also provides a wide spectrum of tools to data visualization and medical visits' segmentation. These tools aim to develop computer-supported medicine by facilitating medical data analysis and iterpretation. The package can be exploited for many applications like the recommendation prediction, patients' clustering etc. that can aid doctors in their practice.

Installation & Dependences

memr is written in R and is based on the following packages:

  • dplyr
  • ggplot2
  • ggrepel
  • Rtsne
  • text2vec

To install memr, simply type in an R console (after having installed the devtools package, e.g. install.package('devtools')):

devtools::install_git("https://github.com/MI2DataLab/memr")

Usage

Example datasets

We show the usage of the package on the example datasets. They are completely artificial, but their structure reflects a structure of the real data collected from Polish health centers. The results of the research on the real data are described in the paper Dobrakowski et al. (2019).

For every visit we can have some information about ICD-10 code of diagnosed disease, ID and specialty of the doctor:

knitr::kable(visits)
visit_id icd10 doctor_id specialties
101 J32 24 endocrinologist, internist
102 Y52 26 endocrinologist
103 X12 24 endocrinologist, internist
104 Q29 24 endocrinologist, internist
105 U46 26 endocrinologist
106 U50 26 endocrinologist
107 I58 25 cardiologist, internist
108 C82 26 endocrinologist
109 P73 24 endocrinologist, internist
110 P66 26 endocrinologist
111 U53 23 ophthalmologist, endocrinologist

For the visits we have also the descriptions of interview with the extracted medical terms:

knitr::kable(interviews)
x
101 fever, eye
102 cough, thyroid
103 fever, thyroid
104 fever, eye
105 cough, thyroid
106 cough, thyroid
107 cough, thyroid
108 rhinitis, eye
109 rhinitis, eye
110 rhinitis, thyroid

Descriptions of examinations of patients:

knitr::kable(examinations)
x
102 mother, father, cough, eye
103 woman, father, rhinitis, thyroid
104 woman, father, fever, thyroid
105 mother, patient, rhinitis, eye
106 man, father, cough, heart
107 woman, father, fever, eye
108 woman, patient, rhinitis, thyroid
109 woman, patient, rhinitis, heart
110 woman, father, cough, heart
111 man, father, rhinitis, eye

And descriptions of recommendations prescribed by doctors to the patients:

knitr::kable(recommendations)
x
103 hospital, endocrinologist
104 hospital, sleep, internist
105 hospital, internist
106 sleep, ophthalmologist
107 hospital, treatment, ophthalmologist
108 treatment, ophthalmologist
109 treatment, hospital, endocrinologist
110 hospital, sleep, cardiologist

Each medical term has one or more categories:

knitr::kable(terms_categories)
term category
man person
woman person
mother person
father person
patient person
cough disease
rhinitis disease
fever disease
sleep recommendation
healthy eating recommendation
hospital recommendation
treatment recommendation
internist specialty
cardiologist specialty
ophthalmologist specialty
endocrinologist specialty
heart anatomic
eye anatomic
thyroid anatomic

Medical terms embeddings

Firstly we can compute embeddings:

embedding_size <- 5

interview_term_vectors <- embed_terms(merged_terms = interviews, embedding_size = embedding_size,
                                       term_count_min = 1L)
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 1, expected cost 0.1305
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 2, expected cost 0.0852
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 3, expected cost 0.0592
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 4, expected cost 0.0426
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 5, expected cost 0.0314
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 6, expected cost 0.0235
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 7, expected cost 0.0180
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 8, expected cost 0.0139
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 9, expected cost 0.0109
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 10, expected cost 0.0087
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 11, expected cost 0.0070
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 12, expected cost 0.0057
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 13, expected cost 0.0047
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 14, expected cost 0.0039
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 15, expected cost 0.0033
examination_term_vectors <- embed_terms(merged_terms = examinations, embedding_size = embedding_size,
                                         term_count_min = 1L)
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 1, expected cost 0.1059
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 2, expected cost 0.0510
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 3, expected cost 0.0315
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 4, expected cost 0.0225
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 5, expected cost 0.0178
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 6, expected cost 0.0149
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 7, expected cost 0.0131
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 8, expected cost 0.0117
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 9, expected cost 0.0107
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 10, expected cost 0.0099
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 11, expected cost 0.0093
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 12, expected cost 0.0087
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 13, expected cost 0.0082
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 14, expected cost 0.0078
#> INFO [2020-03-18 11:43:54] 2020-03-18 11:43:54 - epoch 15, expected cost 0.0074

knitr::kable(interview_term_vectors[1:5, ])
rhinitis -0.4704351 0.0315635 0.5707754 0.2680295 0.2400996
fever -0.3948241 0.3853350 0.5458298 0.2350670 0.4494087
eye 0.4959916 0.0223423 -0.3431036 -0.2673065 -0.2371423
cough -0.0089209 0.3737412 0.0054367 -0.6043935 0.4064513
thyroid -0.1455389 -0.2107478 -0.2871478 -0.3121039 -0.2287994

Terms from the chosen category can be visualized:

visualize_term_embeddings(terms_categories, interview_term_vectors, c("anatomic"), method = "PCA")

To validate the quality of embeddings we can perform the term analogy task (see more by ?analogy_task). The package delivers the analogy test set.

knitr::kable(evaluate_term_embeddings(examination_term_vectors, n = 5, terms_pairs_test))
1 2 3 4 5 MEAN
person 0 0 0 0 0.5000000 0.1000000
spec 0 0 0 0 0.0000000 0.0000000
synonym 0 0 0 0 0.5000000 0.1000000
MEAN 0 0 0 0 0.3333333 0.0666667

For each type of analogy we compute the mean accuracy.

Analogies can be plotted to see if the connection lines are parallel:

visualize_analogies(examination_term_vectors, terms_pairs_test$person, find_analogies = TRUE, n = 10)

Visits embeddings

Having the embeddings of terms, we can compute embeddings of visits:

visits_vectors <- embed_list_visits(interviews, examinations, interview_term_vectors, examination_term_vectors)
knitr::kable(visits_vectors[1:5, ])
101 0.0505837 0.2038387 0.1013631 -0.0161198 0.1061332 NA NA NA NA NA
102 -0.0772299 0.0814967 -0.1408555 -0.4582487 0.0888259 0.1106313 -0.1679365 -0.0600053 0.1011591 0.0932502
103 -0.2701815 0.0872936 0.1293410 -0.0385184 0.1103047 0.1915759 0.1393210 -0.0021371 0.0500974 0.1605039
104 0.0505837 0.2038387 0.1013631 -0.0161198 0.1061332 0.1695910 0.1284853 0.0011363 -0.0126280 -0.0033302
105 -0.0772299 0.0814967 -0.1408555 -0.4582487 0.0888259 0.0037491 -0.0883031 -0.0408950 0.1075936 0.0625818

And now we can visualize the visits on the plot and color by the doctors' IDs:

visualize_visit_embeddings(visits_vectors, visits, color_by = "doctor",
                                spec = "internist")

or by ICD-10 code:

visualize_visit_embeddings(visits_vectors, visits, color_by = "icd10",
                                spec = "internist")

Clustering

On the visits' embeddings we can run the k-means algorithm:

clusters <- cluster_visits(visits_vectors, visits, spec = "internist", cluster_number = 2)

and plot the clusters:

visualize_visit_embeddings(visits_vectors, visits, color_by = "cluster",
                                spec = "internist", clusters = clusters)

For every cluster we can see the most frequent recommendations from chosen categories:

rec_tables <- get_cluster_recommendations(recommendations, clusters,
                                          category = "recommendation",
                                          recom_table = terms_categories)
rec_tables
#> [[1]]
#> # A tibble: 3 x 3
#>   recommendation count frequency
#>   <fct>          <int>     <dbl>
#> 1 hospital           3      0.75
#> 2 sleep              1      0.25
#> 3 treatment          1      0.25
#> 
#> [[2]]
#> # A tibble: 2 x 3
#>   recommendation count frequency
#>   <fct>          <int>     <dbl>
#> 1 hospital           1         1
#> 2 treatment          1         1

or from all categories:

rec_tables <- get_cluster_recommendations(recommendations, clusters, category = "all")
rec_tables
#> [[1]]
#> # A tibble: 5 x 3
#>   recommendation  count frequency
#>   <fct>           <int>     <dbl>
#> 1 hospital            3      0.75
#> 2 endocrinologist     2      0.5 
#> 3 internist           1      0.25
#> 4 sleep               1      0.25
#> 5 treatment           1      0.25
#> 
#> [[2]]
#> # A tibble: 3 x 3
#>   recommendation  count frequency
#>   <fct>           <int>     <dbl>
#> 1 hospital            1         1
#> 2 ophthalmologist     1         1
#> 3 treatment           1         1

If we have a new visit, we can assign it to the most appropriate cluster:

inter_descr <- paste("cough", sep = ", ")
exam_descr <- paste("fever", sep = ", ")
visit_description <- c(inter_descr, exam_descr)
names(visit_description) <- c("inter", "exam")
cl <- assign_visit_to_cluster(visit_description, clusters, interview_term_vectors, examination_term_vectors)
cl
#> $cl
#> 1 
#> 1 
#> 
#> $distances
#>          1          2 
#> 0.07533538 0.24136356

As the last nice thing we can see the embeddings of ICD-10 codes:

visualize_icd10(visits_vectors, visits)

Acknowledgements

The package was created during the research financially supported by the Polish Centre for Research and Development (Grant POIR.01.01.01-00-0328/17).

References

Dobrakowski, Adam, Agnieszka Mykowiecka, Małgorzata Marciniak, Wojciech Jaworski, and Przemysław Biecek. 2019. “Interpretable Segmentation of Medical Free-Text Records Based on Word Embeddings.” arXiv Preprint arXiv:1907.04152. https://arxiv.org/abs/1907.04152.