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Table 3 Word-finding difficulty (clinician-rated) and correlations (p<0.05) with speech variables, ranked by correlation coefficient (Spearman’s |ρ|)

From: Correlating natural language processing and automated speech analysis with clinician assessment to quantify speech-language changes in mild cognitive impairment and Alzheimer’s dementia

Variable type

Variable description

ρ

F1

F2

F3

F4

Lexical

Average word length

− 0.74

   

0.78

Acoustic

Speech rate

− 0.68

    

Acoustic

Average word duration

0.68

 

0.62

  

Acoustic

Number of unfilled pauses

0.63

− 0.68

   

Acoustic

Number of long pauses

0.48

− 0.87

   

Lexical

Use of past tense verbs

0.47

    

Acoustic

Variance of the number of zero crossings

− 0.46

  

− 0.81

 

Acoustic

Skewness of the number of zero crossings

0.46

  

0.91

 

Acoustic

Mean number of zero crossings

− 0.46

  

− 0.79

 

Acoustic

Kurtosis of the number of zero crossings

0.46

  

0.91

 

Acoustic

Total duration of short pauses

− 0.46

0.63

   

Lexical

Ratio of subordinate to coordinate words

0.46

    

Lexical

Average word frequency

0.43

   

− 0.79

Acoustic

Total duration of long pauses

0.43

− 0.87

   

Syntactic

Use of noun phrases with determiners and nouns

0.42

 

0.67

  

Acoustic

Number of short pauses

− 0.42

0.72

   

Syntactic

Use of conjunctive verb phrases

− 0.41

    

Acoustic

Mean pause duration

0.39

− 0.66

   

Lexical

Use of demonstrative words

0.39

    

Syntactic

Use of singular present verb phrases with prepositional phrases

− 0.39

    

Syntactic

Number of coordinate phrases per clause

− 0.39

   

0.72

Lexical

Number of words

0.39

   

− 0.64

Syntactic

Use of coordinate phrases

− 0.38

    

Acoustic

Skewness of the second derivative of the 4th MFCC

− 0.38

 

− 0.85

  

Lexical

Average dominance score of all words

− 0.37

    

Acoustic

Kurtosis of the second derivative of the 4th MFCC

0.37

 

0.94

  

Lexical

Use of comparative adjectives

0.37

    

Syntactic

Use of past tense verb phrases with noun phrases

0.37

 

0.73

  

Acoustic

Mean of the first derivative of the 10th MFCC

− 0.37

    

Lexical

Average dominance scores of nouns

− 0.36

    

Syntactic

Use of adjective phrases

− 0.36

    
  1. Columns F1 to F4 indicate which variables were assigned to each factor and the factor loading scores. Variables that do not have values in any of the columns correlated with word-finding difficulty but were not included in a factor based on the EFA