Table 1.
Studies of Resting Parietal EEG Asymmetry and Depression
| Citation | Sample | Age | Handedness | Reference Scheme and Parietal Sites | Primary Assessment of Depression | Parietal Results Summary | Hemisphere Analysis | Gender Difference Analysis | Comorbid Anxiety Analysis |
|---|---|---|---|---|---|---|---|---|---|
| Allen et al. (1993) | 4 women with bipolar seasonal affective disorder (SAD); 4 female control subjects | Pre-menopausal | Right | Cz; P4-P3 | DSM-III-R criteria | SAD group marginally ↓ RPA than control group | No | No | No |
| Blackhart et al. (2006) | 28 (23 female) | 18-25 | Right | LE; P4-P3 | BDI | ↑ BDI scores predicted ↓ RPA | No | Yes, no effects involving gender found | Yes; participants had no reported history of psychopathology; anxiety symptoms did not predict parietal asymmetry |
| Bruder et al. (1997) | 19 anxious-depressed (9 female); 25 non-anxious depressed (13 female); 26 control subjects (13 female) | 20-60 | 50 right and 10 left | Cz, Nose; P4-P3, P8-P7 | DSM-III-R criteria | Anxious-depressed ↑ RPA than LPA; Non-anxious-depressed ↓ RPA than LPA; controls showed parietal symmetry; non-anxious depressed ↓ RPA than anxious-depressed | Yes | No | Yes; addressed in main analysis with anxiety groups; also found no relationship between STAI and asymmetry |
| Bruder et al. (2005) | 18 offspring of 2 parents with MDD (10 female); 40 offspring of 1 parent with MDD (25 female); 29 controls with no MDD parents (18 female) | 8-50 | Right | LE; P4-P3, P8-P7 | DSM-IV criteria | Offspring of 2 parents with MDD ↓ RPA than offspring of 1 parent with MDD and controls | Yes | No | Yes; anxiety symptoms did not moderate results |
| Bruder et al. (2007) | 19 (11 female) offspring having parent and grandparent with MDD; 14 (6 female) offspring having parent or grandparent with MDD; 16 (9 female) offspring with neither parent or grandparent with MDD | Right | Offspring with 2 MDD relatives M = 15.4, SD = 4.7; offspring with 1 MDD relative M = 13.6, SD = 6.2; controls M = 10.6, SD = 4.5 | LE; P4-P3, P8-P7 | DSM-IV criteria | Offspring of 2 MDD relatives ↓ RPA than other 2 groups | Yes | Yes, no effects involving gender found | Yes; results remain when subjects with lifetime anxiety diagnoses are removed from analysis |
| Dawson et al. (1997) | 117 infants (52 female), 54 with MDD mothers and 63 non-MDD mothers | Not reported | 13-15 months | LM; P4-P3 | DSM-III-R criteria | No significant findings | Yes | Yes; Male infants of non-MDD mothers ↑ RPA than female infants; Female infants of MDD mothers ↑ RPA than male infants of MDD mothers | Yes, anxiety accounted for in analyses |
| Debener et al. (2000) | 15 current MDD (10 female); 22 controls (15 female) | 33 right; 4 left | 23-64 | LM; P4-P3 | ICD criteria | No significant findings | Yes | No | No |
| Deslandes et al. (2008) | 22 depressed and 14 controls | Right | > 60 | LE; P4-P3 | DSM-IV criteria | No significant findings | Yes | No | No |
| Diego et al. (2001) | 163 women | 83% right | M = 23 (SD = 5) | Cz; P4-P3 | Center for Epidemiological Studies Depression Scale | No significant findings | Reported for frontal, not parietal EEG analyses | No | No |
| Diego et al. (2004) | Babies of 20 prepartum and postpartum depressed mothers (58% male), 20 prepartum depressed mothers (35% male), 20 postpartum depressed mothers (40% male), and 20 non-depressed mothers (40% male) | Not reported | M = 1.7 weeks (SD = 0.8 weeks) | Cz; P4-P3 | Center for Epidemiological Studies Depression Scale | No significant findings | No | No | No |
| Field et al. (1995) | 17 infants of depressed mothers; 17 infants of non-depressed mothers | Right-handed parents | 3-6 months | Cz; P4-P3 | BDI and Diagnostic Interview Schedule for Children | No significant findings | Yes | No | No |
| Graae et al. (1996) | 16 female suicide attempters; 22 female controls | Right | 12-17 | Nose; P4-P3 | BDI and Diagnostic Interview Schedule for Children | ↓ RPA linked to higher suicidal intent, not depressive symptoms | Yes | No | No |
| Harmon-Jones et al. (2002) | 72 (37 female) | Right | Not reported | LE; P4-P3 | General Behavior Inventory Depression scale | No significant findings | Reported for frontal, not parietal EEG analyses | No | Accounted for baseline reported fear |
| Henriques & Davidson (1990) | 6 euthymic depressed patients (5 female); 8 controls (6 female) | Right | Depressed M = 37.4, SD = 9.5; Controls M = 34.7, SD = 3.4 | AVG, Cz, LM; P4-P3 | Schedule for Affective Disorders and Schizophrenia according to Research Diagnostic Criteria | MDD group ↓ RPA than control group | Yes | No | No |
| Henriques & Davidson (1991) | 15 MDD patients (8 female); 13 controls (9 female) | Right | 31-57 | AVG, Cz, LE; P4-P3 | Schedule for Affective Disorders and Schizophrenia according to Research Diagnostic Criteria | No significant findings | Yes | No | No |
| Jones et al. (1997) | 20 infants of depressed mothers; 24 infants of non-depressed mothers (gender not reported) | Not reported | 1-3 months | Cz; P4-P3 | Center for Epidemiological Studies Depression Scale | No significant findings | Yes | No | No |
| Jones et al. (1998) | 35 infants (57.9% male) of depressed mothers; 28 infants (46.2% male) of non-depressed mothers | Not reported | 1 week | Cz, P4-P3 | Center for Epidemiological Studies Depression Scale | No significant findings | Yes | No | No |
| Kentgen et al. (2000) | 11 women with current MDD and comorbid anxiety disorder; 8 women with current MDD and no anxiety disorder; 6 women with no current MDD and an anxiety disorder; 10 female controls | Right | 12-19 | Cz, Nose; P4-P3, P8-P7 | DSM-IV criteria | Subjects with MDD but no anxiety disorder showed ↓ RPA than LPA | Yes | No | Yes; addressed in main analysis with anxiety groups |
| Mathersul et al. (2008) | 428 (214 female) separated into Normal (n = 52), Depressed (n = 52), Anxious (n = 52) and Comorbid (n = 52) groups | Not reported | 18-60 | AVG; T6-T5 and P4-P3 averaged together | Depression Anxiety Stress Scales (21 item version) depression scale | Depressed and comorbid anxiety-depression groups ↑ RPA than control group | Yes | None examining gender × group to predict EEG | Yes; addressed in main analysis with anxiety groups |
| Metzger et al. (2004) | 50 female Vietnam War nurse veterans, 18 with current PTSD (9 with comorbid lifetime MDD), 14 with past PTSD (7 with comorbid lifetime MDD), and 18 with no PTSD (5 with lifetime MDD). All groups included other comorbid anxious disorders. | Right | M = 53.7, SD = 2.8 | LE; P4-P3 | DSM-IV; Clinician- Administered PTSD Scale; Symptom Checklist-90-Revised | Higher PTSD arousal symptoms ↑ RPA; PTSD arousal and PTSD arousal by depression interaction accounted for 25% of the variance in RPA | No. | No | Yes. Discussed failure to find link between higher depression symptoms ↓ RPA may be due to lack of depressed subjects without high arousal |
| Miller et al. (2002) | 55 with child onset MDD or dysthymia (28 female); 55 controls (38 female) | 85% right-handed | Depressed M = 26.0 (SD = 3.2); Control M = 27.2 (SD = 5.8) | AVG; P4-P3, P8-P7 | DSM-III and DSM-IV | No significant findings | Yes | Did examine them in frontal regions but unclear with regard to parietal | Yes; anxiety symptoms did not moderate results |
| Nitschke et al. (1999) | 9 anxious apprehension (6 female), 19 anxious arousal (10 female), 12 depressed (9 female), 13 comorbid (6 female), 14 (8 female) | Right | 17-20 | LM; P4-P3 | Mood and Anxiety Symptom Questionnaire, Anhedonic Depression scale | No significant findings for depressed group once 2 male outliers were removed | Yes | Yes, no gender effects emerged | Yes; addressed in main analysis with anxiety groups |
| Pössel et al. (2008) | 80 adolescents (35 female) | Right | 13-15 | Nose; P4-P3 | Depression-Screening Questionnaire and Self-Rating Questionnaire for Depressive Disorders based on ICD-10 and DSM-IV criteria | ↑ RPA predicted depression symptoms 12 months later | No | No | Yes, accounted for anxiety in depression analyses |
| Reid et al. (1998) | Study 1: 19 low BDI women and 17 high BDI women; Study 2: 13 women with MDD and 14 controls | Right | Study 1: Low BDI group M = 19.1 (SD = 1.1) and High BDI group M = 17.9 (SD = 0.2); Study 2: MDD group M = 27.5 (SD = 8.1) and control group M = 27.6 (SD = 7.5) | AVG, Cz, LM; P4-P3 | Study 1: BDI; Study 2: DSM-III-R | Study 1: No significant findings; Study 2: MDD group ↓ RPA than control group (LM) | No | No | No |
| Schaffer et al. (1983) | 6 high BDI scorers (4 female); 6 low BDI scorers (4 female) | Not reported | Not reported | Cz; P4-P3 | BDI | No significant findings | No | No | No |
| Shankman et al. (2005) | 12 low positive emotionality (PE; 58% female) and 17 high PE group (44% female) | 73.2% right-handed | Age 3 and follow-up at age 5-6 | LM; P4-P3, P8-P7 | Positive Emotionality score based on tests in the Laboratory Temperament Assessment Battery | Low PE group showed ↓ RPA than LPA | Yes | Yes, no gender effects emerged | Neuroticism not related to asymmetry |
| Tomarken et al. (2004) | 25 offspring of MDD mothers (14 female); 13 offspring of mothers with no MDD (6 female) | Right | 12-14 | AVG, Cz, LE; P4-P3 | DSM-III-R | High risk group associated with ↑ RPA (Cz) | Reported for frontal, not parietal EEG analyses | Yes, but did not mention gender differences in parietal asymmetry | No |
| Volf & Passynkova (2002) | 31 MDD/SAD patients (29 females); 30 matched controls | Right | 28-55 | LE; P4-P3 | DSM-III-R | MDD/SAD group ↓ BPA than controls | Yes | No | No |
Notes: MDD= major depressive disorder. LPA = left parietal activity. RPA = right parietal activity. BPA = bilateral parietal activity. BDI = Beck Depression Inventory. DSM = Diagnostic and Statistical Manual. ICD= International Classification of Diseases. STAI = State Trait Anxiety Inventory. SAD = seasonal affective disorder. AVG = average reference. LE = linked ears reference. LM = linked mastoids reference.